Class 10 Maths – Chapter 6: Triangles (60 MCQs)
Triangles (Similarity) — 60 MCQs
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1Two figures having the same shape but not necessarily the same size are called:Correct ✅Incorrect ✖
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(b) Similar figures — Two figures have same shape (not necessarily size). -
2All congruent figures are:Correct ✅Incorrect ✖
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(b) Similar — congruence implies similarity. -
3All circles are:Correct ✅Incorrect ✖
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(b) Similar — all circles have same shape. -
4All squares are:Correct ✅Incorrect ✖
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(a) Similar only — squares of different sizes are similar; congruent only if side lengths equal. -
5All equilateral triangles are:Correct ✅Incorrect ✖
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(b) Similar — equilateral triangles have same angles. -
6A square and a rhombus are not similar because:Correct ✅Incorrect ✖
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(c) Both — shape differs unless it's a square (special rhombus). -
7Two polygons of the same number of sides are similar if:Correct ✅Incorrect ✖
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(c) Both — both conditions required for polygon similarity. -
8The constant ratio of corresponding sides of similar figures is called:Correct ✅Incorrect ✖
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(a) Scale factor — also called representative fraction. -
9World maps are drawn using:Correct ✅Incorrect ✖
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(a) Similarity — maps use scales (similarity ratios). -
10The shadow of an object forms:Correct ✅Incorrect ✖
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(b) A similar figure — shadow keeps shape, scales size. -
11If one polygon is similar to a second and the second is similar to a third, then:Correct ✅Incorrect ✖
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(b) First and third are similar — similarity is transitive. -
12In quadrilaterals, equality of corresponding angles alone is:Correct ✅Incorrect ✖
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(b) Not sufficient — sides must also be proportional. -
13In quadrilaterals, proportionality of corresponding sides alone is:Correct ✅Incorrect ✖
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(b) Not sufficient — angles must match too for polygon similarity. -
14A photograph of the same object printed in different sizes shows:Correct ✅Incorrect ✖
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(b) Similarity — shape preserved, size changed by scale factor. -
15Scale factor of a figure enlarged from 35 mm to 45 mm is:Correct ✅Incorrect ✖
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(a) 45/35 — new length divided by original length. -
16Two triangles are similar if:Correct ✅Incorrect ✖
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(b) Both conditions — equal angles and proportional sides. -
17Equiangular triangles are always:Correct ✅Incorrect ✖
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(b) Similar — same angles imply proportional sides (Thales/BPT idea). -
18Thales’ theorem is also called:Correct ✅Incorrect ✖
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(b) Basic Proportionality Theorem — line parallel to one side divides other sides proportionally. -
19In ΔABC, DE ∥ BC ⇒ AD/DB =:Correct ✅Incorrect ✖
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(a) AE/EC — Basic Proportionality Theorem result. -
20Theorem 6.1 states:Correct ✅Incorrect ✖
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(a) That is exactly Theorem 6.1 (Basic Proportionality Theorem). -
21Converse of Theorem 6.1 (Theorem 6.2):Correct ✅Incorrect ✖
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(a) Theorem 6.2 is the converse: equal ratios imply parallel. -
22A trapezium ABCD with AB ∥ DC and EF ∥ AB, then:Correct ✅Incorrect ✖
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(a) AE/ED = BF/FC — from similar triangles in trapezium construction. -
23If PS/SQ = PT/TR and ∠PST = ∠PRQ, then ΔPQR is:Correct ✅Incorrect ✖
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(b) Isosceles — leads to equal base angles so two sides equal. -
24Using Theorem 6.1, a line through midpoint of one side ∥ another side will:Correct ✅Incorrect ✖
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(a) Bisect third side — median parallel to side bisects the third side. -
25If diagonals intersect with AO/BO = CO/DO, the quadrilateral is:Correct ✅Incorrect ✖
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(b) Trapezium — that ratio condition implies one pair of opposite sides parallel. -
26If DE ∥ BC in ΔABC ⇒ AD/AB =:Correct ✅Incorrect ✖
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(a) AE/AC — rearranged from theorem result AD/AB = AE/AC. -
27If a line divides two sides in equal ratio, it must be:Correct ✅Incorrect ✖
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(b) Parallel to third side — converse of BPT. -
28The symbol used for similarity of triangles:Correct ✅Incorrect ✖
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(c) ~ — e.g., ΔABC ~ ΔDEF. -
29ΔABC ~ ΔDEF implies:Correct ✅Incorrect ✖
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(c) Both — corresponding angles equal and sides proportional. -
30Similarity relation must always be written with:Correct ✅Incorrect ✖
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(b) Correct correspondence — order matters to show which vertex corresponds to which. -
31AAA criterion means:Correct ✅Incorrect ✖
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(b) AAA — equal angles imply similarity. -
32AA criterion states:Correct ✅Incorrect ✖
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(a) AA — two angles equal implies third equal by angle sum; triangles similar. -
33SSS similarity criterion means:Correct ✅Incorrect ✖
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(a) Sides proportional ⇒ angles equal ⇒ similarity. -
34SAS similarity criterion states:Correct ✅Incorrect ✖
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(a) SAS — equal included angle + proportional adjacent sides. -
35RHS similarity criterion applies to:Correct ✅Incorrect ✖
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(a) Right triangles only — hypotenuse and one side proportional gives similarity. -
36If AB/DE = AC/DF and ∠A = ∠D ⇒ ΔABC ~ ΔDEF by:Correct ✅Incorrect ✖
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(a) SAS similarity. -
37If ΔABC ~ ΔPQR ⇒ then CM/RN =:Correct ✅Incorrect ✖
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(c) Both — medians scale same as corresponding sides in similar triangles. -
38In ΔABC and ΔDEF, if ∠A = ∠D, ∠B = ∠E, ∠C = ∠F ⇒ triangles similar by:Correct ✅Incorrect ✖
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(b) AAA — equal corresponding angles imply similarity. -
39If AB/DE = BC/EF = AC/DF ⇒ triangles are similar by:Correct ✅Incorrect ✖
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(a) SSS similarity criterion. -
40In ΔABC and ΔPQR, if ∠A = ∠P and AB/PQ = AC/PR ⇒ similarity criterion is:Correct ✅Incorrect ✖
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(a) SAS — included angle and adjacent sides proportional. -
41In two right triangles, if hypotenuse and one side proportional ⇒ triangles similar by:Correct ✅Incorrect ✖
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(b) RHS — right triangle similarity criterion. -
42ΔPOQ ~ ΔSOR if PQ ∥ RS because:Correct ✅Incorrect ✖
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(a) Because PQ ∥ RS gives corresponding equal angles (alternate & vertical). -
43If ΔABC ~ ΔRQP ⇒ ∠C = ∠P due to:Correct ✅Incorrect ✖
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(a) AAA — corresponding angles equal in similar triangles. -
44A 6 m pole casts 4 m shadow; tower casts 28 m shadow ⇒ height of tower is:Correct ✅Incorrect ✖
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Scale factor = 28/4 = 7; tower height = 6 * 7 = 42 m ⇒ (b). -
45A girl of height 90 cm, lamp-post of 3.6 m ⇒ after 4 s walking (4.8 m away), shadow length =:Correct ✅Incorrect ✖
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Using similar triangles: (4.8+x)/x = 3.6/0.9 = 4 ⇒ x = 1.6 m ⇒ (b). -
46Similarity is based on:Correct ✅Incorrect ✖
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(a) Shape — similar figures have same shape (sizes may differ). -
47Congruence implies:Correct ✅Incorrect ✖
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(a) Similarity always — congruent figures are same shape and size, hence similar. -
48Two photos of same person (age 10 and 40) are:Correct ✅Incorrect ✖
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(b) Not similar — shape changes with age even if sizes are same. -
49A square and rectangle are not similar because:Correct ✅Incorrect ✖
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(a) Sides not proportional — rectangle sides ratio differs from 1:1 of square. -
50A line parallel to one side of triangle divides:Correct ✅Incorrect ✖
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(a) Other two sides proportionally — Basic Proportionality Theorem. -
51In ΔABC, DE ∥ BC ⇒ AD/DB = AE/EC shows:Correct ✅Incorrect ✖
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(a) BPT — Basic Proportionality Theorem. -
52The converse of Basic Proportionality Theorem is:Correct ✅Incorrect ✖
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(a) That is Theorem 6.2, the converse. -
53Triangles are denoted similar using symbol:Correct ✅Incorrect ✖
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(a) ~ — e.g., ΔABC ~ ΔDEF. -
54In similar triangles, ratio of altitudes is equal to:Correct ✅Incorrect ✖
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(a) Ratio of sides — all linear measures scale by same factor. -
55If ΔABC ~ ΔPQR ⇒ then ratio of medians =:Correct ✅Incorrect ✖
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(c) Both — medians scale in same ratio as corresponding sides. -
56If ΔABC ~ ΔPQR ⇒ then ratio of perimeters =:Correct ✅Incorrect ✖
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(a) Ratio of sides — perimeter scales by the same linear ratio. -
57If ΔABC ~ ΔPQR ⇒ then ratio of areas =:Correct ✅Incorrect ✖
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(a) Square of side ratio — area scales with square of linear scale factor. -
58The scale factor is also called:Correct ✅Incorrect ✖
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(a) Representative Fraction — often used in maps/blueprints. -
59Example of indirect measurement using similarity:Correct ✅Incorrect ✖
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(c) Both — indirect measurements often use similar triangles/ratio methods. -
60Which theorem is applied in proving Pythagoras theorem using similarity?Correct ✅Incorrect ✖
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(c) AAA/Similarity arguments — similarity of triangles is used in many proofs of Pythagoras.
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