 Prologue
 [Block#3] Geometry + Trig.
 [Block#4] Misc.Topix
 Epilogue
 Appendix Download link: Topic wise Sorted NCERTs
Prologue
 In the first article, we saw how to prepare number system, surdsindices, linear and quadratic equations for CDS maths paper. click me
 Now in the second article, we’ll see how to approach percentage, profitloss, simplecompound interest rate, timespeeddistancework and statisticsData interpretation related problems. click me
 in this third and last article, we’ll see how to approach geometry, trigonometry and remaining misc. Topics.
[Block#3] Geometry + Trig.
topics in this block  avg. MCQs in each of the last four CDS exams.  priority 
Geometry  36  highest of all topics 
Trigonometry  14  2^{nd} highest of all topics 
You should prepare this block only after finishing earlier block because
 Some of the geometry MCQ require understanding of percentages, ratios and linear equations.
 Some of the trigonometry MCQ require understanding of quadratic equations and geometry.
[Geo] AVP/Mensuration
Officially called “Mensuration”, this involves
 Area and perimeter (A+P) of 2D figures: triangles, squares, rectangles, parallelogram, hexagons
 Surface area, volume and perimeter (A+V+P) of 3D figures: spheres, cones, cylinders. Occasionally prism (tents), frustums (buckets) and pyramids.
Approach
 From all the following NCERT chapters, memorize all the formulas given in the end summary of every chapter. Better write them down in your diary of mistakes.
 for class 9 and class 10 NCERT chapters given below, you must solve all the examples and exercises given in them
 Avoid silly mistakes e.g.
 putting value of diameter instead of radius in the formula
 not converting everything in same unit (cm/m/km)
7_11_Perimeter and Area  Basics about areaperimeters of parallelograms and circles.  IAK 
8_11_Mensuration Modified  Area of Trapezium, polygon. General formula for quadrilaterals via diagonals.  DQ 
8_11_Mensuration Modified  Cube, Cuboid and Cylinder their area Volume and Capacity.  DQ  IAK 
9_12_Herons formula  for finding area using ‘semiperimeter’ concept for triangles and Quadrilaterals.  DQ  IAK 
9_13_Surface areas and volumes  of cuboid, cylinder, cone, sphere. Solve all the examples and exercises from this chapter.  DQ  IAK 
10_12 Areas Related to Circles  Solve all the problem figures given in this chapter.  DQ 
10_13_Surface Areas and Volumes  More complex sums involving combination of solids e.g. two half spheres and a cylinder in between etc. Solve all the examples and exercises given in this chapter  DQ* 
After this goto Sarvesh Kumar’s chapter on Mensuration and Solve all the examples, introductory exercises and level 1 exercises. Note: he has given a big table at the beginning of this chapter, dealing with area, perimeter – Memorize it entirely.
*abbreviations used in above table
 “7_11 Perimeter and Area”= class 7 maths textbook, chapter 11
 DQ=direct questions asked in CDS from the theory/definition/examples given in this chapter. Hence even if you “know” the topic, DO go through those chapters.
 IAK=”I already know”. Meaning you can ignore this chapter, if you’re basics are already good. (i.e. you’ve already cleared written stage of bank, SSC or LIC.)
 “Bold”: topics highlighted in bold are MUST DO, Most important because MCQs routinely appearing from there.
Observe the MCQs from past CDS exams
TRIANGLES  QUADRILATERAL 


Circle  Sphere 


CYLINDER  CONE / FRUSTUM 


+ Variety of diagram/figure based questions. But for the lack of time, I’m not inserting their scanned photos here in the article.
[Geo] theory / nonAVP
 Questions involving sides, angles, midpoints, bisectors, centroid etc. topics related to 2D figures (lines, triangles, quadrilaterals and circles.)
 In CDS, usually they give a problem figure that has one or more combination of triangle + parallelogram + circle. So, first you need master the individual figures (triangles, parallelogram and circle) before you attempt the MCQs involving their combination.
[Geo_theory1]Lines and Angles
Superficially this might look like a ‘chillar’ topic but good number of MCQs come every year from here.
7_5 Lines and Angles  types of angles, pair of angles  IAK 
9_6_Lines and angle  Intersecting lines and the angels made by them. corresponding, interior etc.  IAK 
9_5_Introduction to Euclid’s geometry  basics of axioms and theorem  IAK 
Then move to Sarevsh Kumar=>Geometry=> starting part of the chapter and the big table of linesangle and first introductory exercise.
Observe the MCQs from past CDS exams
 Three lines intersect each other in pairs. What is the number of angles so formed? (3/6/9/12)
 Assertion (A) two distinct lines cannot have more than one point in common. Reasoning (R) any number of lines can be drawn through one point.
 What is the least number of straight lines for a bounded plane figure?(1/2/3/4)
 What is the angle which equals one –fifth of its supplement (15/30/36/75)
 If two parallel lines are intersected by a transversal, then
 Each pair of corresponding angles are equal.
 each pair of alternate are unequal.
 both A and B correct
 None
 + Variety of diagram/figure based questions. But for the lack of time, I’m not inserting them here in the article.
[Geo_theory2] Triangles
Similarity and congruence are most important because in variety of MCQ figures involving – you’ll have to apply these concepts to get the value of any side/angle/area. Master them from NCERTs.
7_6 The Triangle and its Properties  altitude, angle sum property, sums of sides and inequalities related to it, Pythagoras  IAK 
7_7 Congruence of Triangles  SSS, SAS, ASA congruence  IAK 
9_7_Triangles  advanced concepts related to Congruence, sidesaltitude and base  DQ 
9_12_Herons formula  for finding area using ‘semiperimeter’ concept for triangles and Quadrilaterals. Mugup the Summary  DQ  IAK 
10_6 Triangles  Similarity of triangles/  DQ 
Then, Sarevsh Kumar=>Geometry=>Triangle related table and introductory exercises.
 Mugup the table related to altitude, median, angle bisector, circumcenter / orthocenter/ incenter/ centroid of a triangle.
 He has also given a separate table important theorems on triangles. Within that important are:
 BPT, midpoint, Apollonius, interior exterior bisector.
 You can ignore 454590 and 306090 theorem because I’ve already covered its applications in trigonometry – in separate articles and videos.
Triangles: Demo MCQs from previous exam
 The point of concurrence of the altitudes of a triangle is called? (circumcenter / orthocenter/ incenter/ centroid)
 find correct statement
 Congruent triangles are similar.
 If the hypotenuse and a side of one right triangle are equal to the hypotenuse and a side of another right triangle respectively, then the two right triangles are congruent.
 both A and B
 neither A nor B
 What is the number of points in the plane of a triangle ABC are at equal distance from the vertices of the triangle?
 Assertion (A) If two triangles are congruent, then their corresponding angles are equal. Reason (R) Two congruent triangles have same area.
 A triangle DEF is formed by joining the midpoints of the sides of triangle ABC. Similarly a triangle PQR is formed by joining the midpoints of the sides of the triangle DEF. If the sides of the triangle PQR are of lengths 1, 2 and 3 units, what is the perimeter of the triangle ABC?
 18 units
 24 units
 48 units
 Cannot be determined due to insufficient data
 The centroid of a triangle ABC is 8cm from the vertex A. What is the length of the median of the triangle through A?
 A piece of wire 78 cm long is bent in the form of an isosceles triangle. If the ratio of one of the equal sides to the base is 5:3, then what is the length of the base?
 + Variety of diagram/figure based questions. But for the lack of time, I’m not inserting their scanned photos here in the article.
[Geo_theory3]Quadrilaterals
Quadrilateral means four sided 2D figure: square, rectangle, kite, trapezium, rhombus etc.
8_3 Understanding Quadrilaterals  Anglesum property, exterior angles, Parallelogram: diagonals, sides, angles, rhombus. properties of quadrilaterals (given at bottom of chapter)  DQ 
9_8_Quadrilaterals  Theorems related to quadrilaterals, diagonals, midpoints, bisectors  DQ 
9_9_Areas of parallelograms and triangles  this is not related to ‘formulas’ but theory about trianglesparallelograms on same base, one figure inside another etc. must be thoroughly prepared  DQ 
8_10 Visualizing Shapes_euler’s formula  only one topic: Euler’s formula for polyhedron (F+VE=2), given under topic Number 10.4  DQ 
Then Sarevsh Kumar=>Geometry=>Quadrilaterals related table and introductory exercises.
He has summarized the bullets related to quadrilateral properties. Religiously memorize them for the theory/definition based MCQs. also do the ‘polygon’ related section – particularly the table about sum of all angles, no. of diagonals for triangle, quadri., pentagon, hexagon etc.
Triangles: Demo MCQs from previous CDS exams
1.Find correct statement

2.Correct statement about quadrilateral

3.ABCD is a quadrilateral such that BC = BA and CD > AD. Which one of the following is correct?

4.Assertion (A) if the sides of a rhombus is 10 cm. its diagonals should have values of 16cm and 12 cm. Reason(R) The diagonals of a rhombus cut at right angles.5. + Variety of diagram/figure based questions. But for the lack of time, I’m not inserting their scanned photos here in the article. 
[Geo_theory4]Circles
Another prominent topic under geometry MCQs. Often the problem figure would involve a triangle / quadrilateral embedded inside the circle. Hence, circle topic should be prepared only after mastering triangles and quadrilaterals topics first.
9_10_Circles 

DQ 

DQ  

DQ  
10_10 Circles  number of tangents from a circle  DQ 
After this, Sarvesh Kumar=>Geometry=>Circles and the introductory exercises. And memorize the table on circle theorems. That’ll help you directly solve variety of MCQs problem figures of circles+ (triangle/quadrilateral) combinations without having to do any calculations.
Once you’re finished with circle’s introductory exercises. do the level 1 sums from Geometry chapter. (and if you’ve time and mood even do level2 for additional grip.)
Circles: Demo MCQs from previous CDS exams
A regular hexagon is inscribed in a circle of radius 5 cm. If x is the area inside the circle but outside the regular hexagon, then which one of the following is correct?

The diameter of a circle with centre at C is 50 cm. CF is a radial segment of the circle. AB is a chord perpendicular to CP and passes through P. CP produced intersects the circle at D. If DP = 18 cm, then what is the length of AB?



Trigonometry
Trigonometry is an important topic for both CDS as well as SSCCGL. but there are few differences
 CDS doesn’t ask question on minimummaximum values. (Atleast I didn’t notice in last five years’ papers)
 CDS asks less questions from height distance and more questions from trig+algebra combo question.
 CDS asks quadrant –sign based question (usually ignored in SSC CGL)
Anyways, how to approach?
First finish geometry and quadratic topics. Because many of these trig.MCQs require understanding of previous two blocks.
[Trig] Height and Distance (HnD)
observe the sample questions from past CDS exams
A radio transmitter antenna of height 100m stands at the top of a tall building.At a point on the ground,the angle of elevation of bottom of the antenna is 45degrees and that of top of antenna is 60degrees.What is the height of the building?  The angle of elevation of the top of a tower from the bottom of a building is twice that from its top. What is the height of the building, if the height of the tower is 75m and the angle of elevation of the top of the tower from the bottom of the building is 60 degrees? 
in every CDS exam, alteast onetwo MCQs are from this “heightdistance” subtopic of trigonometry, To solve them, go through following articles cum YouTube videos (and solve all the questions given at the bottom of each article)
 [Trigonometry] Introduction, Types of Questions, Shortcut for memorizing 30,45,60 for SSC CGL CDS
 [Trigonometry] HnD Type #1: One Building One Angle finding height, distance or hypotenuse
 [Trigonometry] HnD Type #2: Broken Trees and Telegraph Poles: Finding original height
 [Trigonometry] HnD Type #3: One Building Two Angles made easy for SSC
 [Trigonometry] HnD Type #4: Two BuildingsTwo Angles made easy for SSC
 [Trigonometry] HnD Type #5: Finding speed, time or distance made easy for SSC
^in the mock questions given in articles, I’ve covered all the good questions from NCERT. Still if you want to go through NCERTs, they’re included in the zip file.
 10_8 Introduction to Trigonometry
 10_9 Some Applications of Trigonometry
for additional practice: Sarvesh Kumar, and/or old papers for CDS, SSC.
[Trig] nonheight distance
First observe MCQs from past exams
TYPE#2: TABLE (VALUE) BASED  TYPE#3: COMPLIMENTARY ANGLES 


TYPE#4: COMBO OF TRIG+ ALGEBRA  Type#5: Degrees and radians 


TYPE#6: QUADRANTS  
Q.for the first quadrant, which of the following correct?

Q.if cosA is greater than or equal to 1/2 in first quadrant then which of the following correct?

How to approach type 2 to 4
Go through these articles and solve all the questions given at bottom of each article
 [Trigonometry] Type#2: Table based questions, memorization technique, approach explained for SSC CGL
 [Trigonometry] Type#3: Complimentary Angles related Questions and approach for SSC CGL
 [Trigonometry] Type#4: Questions based on Trig and Algebra combo
For additional practice: Sarvesh Kumar, and/or old papers for CDS, SSC.
HOW TO APPROACH TYPE 5 (Quadrants)?
 NCERT class 11 ch.3 Trigonometric Functions: page 50 to55 (included in the zip file) solve all the sums as well.
 and / or Savesh Kumar’s chapter on trigonometry
HOW TO APPROACH TYPE 6 (radians / degrees)?
 NCERT class 11 ch.3 Trigonometric Functions: page 55 to59 (include in the zip file).
 and / or Sarvesh Kumar chapter on trigonometry
[Block#4] Misc.Topix
Overall lowest priority because the following topics, barely 23 MCQs come. Although their cost:benefit is still good (compared to amount of pages you’ve to mupup to get one geography question right) so, When you’re finished with everything else and still have time and mood, do go through these topics.
#1: Set Theory / Venn Diagrams
Usually 23 MCQs per exam. Although NCERT class 10 chapter 15 does cover settheory but to save time, just mugup the bullets given in Sarvesh Kumar’s chapter on Set Theory and solve the practice sums.
Observe the MCQs from previous exam:
set theory  Venn diagram 


#2: Logarithms
 Questions not seen in the recent years and at most one MCQ comes. Although if you’re left with free time, doesn’t take much effort to master.
 for this directly go through Logarithm chapter in Sarvesh Kumar’s book, ignore details related to graphs and characteristics of Mantissa. Solve upto introductory exercise only.
Logarithms: Demo Q. from previous CDS exams:
 What is the value of [5 log_{10} 100]^{2}?
 If log_{r}6=m and log_{r}3=n, then what is log_{r}(r/2)equal to?
 What is the value of [Log_{13}(10)]/[Log_{169}(10)]?
 What is the value of Log_{100}0.1
#3: APGP Progression
Arithmetic progression (AP)  geometric progression (GP) 
if the 14^{th} term of an arithmetic series is 6 and 6^{th} term is 14 then what is the 95^{th} term?  a ball is dropped from the height of 64m above the ground, and every time it hits the ground, it raises to a height equal to half of the previous. What is the height attained after it hits the ground for 16^{th} time? 
APGP are not asked on regular basis but once in a while randomly appear.
I’ve included the respective NCERT chapters from class 10 and 11. but to save time you may just directly go to Sarvesh Kumar’s chapter on “Sequence, series and progressions” : memorize the formulas and solve introductory exercises only.
Topics to ignore
 Permutation Combination Probability
 Coordinate Geometry
Because from above topics, I didn’t see any MCQs in recent years’ CDS papers. (or may be I didn’t look carefully!)
Epilogue
Epilogue, concluding words, sacred rules, unwanted advice, whatever you want to call it….
Rule#1: Must finish entire block in one go
 Suppose today you finished ‘triangle’ topic under geometry. Then you take a ‘break’ and focus on polity for next 23 day, then some history, geography etc. Later you resume back geometry, prepare quadrilaterals after a week.= This type of scattered preparation won’t help you get a steel grip over mathematics.
 You’ve to finish entire block in one go (e.g. picked up geometry then do triangles, quadrilaterals, circles, areavolumeperimeter… everything continuously.)
Rule#2: Winners don’t make excuses
EXCUSES  WHY #EPICFAIL? 
Maths is not my cup of tea. so, I’ll pay extra attention to GS/GK and English to clear this exam. 

I’ve so many things to prepare in current affairs, I’m unable to take out time for maths! 

Hotaa hai, chaltaa hai, thik hai, dekhenge, abhi bahot der hai,there is still lot of time left.  No. Today is 14th Dec. CDS(I)2013 is on 9th February 2013= that’s ~55 days =~8 weeks. You cannot afford to continue preparation in a casual manner anymore. Must pump maximum hours per day in readingrevisionpractice. 
Rules#3: Must get hands dirty, must maintain a diary of mistakes
Why? Explained in following link https://mrunal.org/2012/03/strategyartofpreparingforaptitude.html
Rules#4: Must solve alteast 3 previous papers
Once you finish the maths syllabus. download and solve atleast three original UPSC CDS maths paper from their official site within three hours time limit for each. At home, you can take 51015 minutes to solve one sum but in the exam hall you cannot waste time like that. Sometimes it is better to leave a question involving lengthy calculation (or leave it for the end part of the exam). sometimes, if your answer doesn’t match any of the a/b/c/d option in the exam, then it’s better to move to next question rather than trying to find out the mistake. You can understand these lessons only after burning your hands on original papers. so Do solve previous paperswithin the given time limit.
Appendix Download link: Topic wise Sorted NCERTs
You’ve two choices
Choice #1: good internet connection: And you want to download entire zip file at once (size 35MB) then use following link: https://files.secureserver.net/0sYHJ029rgUbrg
Choice #2: not so good internet connection: and / or You want to download small zip files or selective topics only, then goto following link (e.g. geometry zip file separately, trigonometry zip file separately and so on) then use following link: https://files.secureserver.net/0fmaNqqBDslHlc