Class 10 Mathematics (NCERT)

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Ch-6: Triangles 30 Questions

Before You Practice

Try each question on your own first. Use the Show Answer button only after you have selected your option, then read the explanation and revise the related concept from your chapter notes.

1. All circles are always:

  • A. Congruent
  • B. Similar
  • C. Equal in area
  • D. Neither similar nor congruent

2. All squares are:

  • A. Congruent
  • B. Similar
  • C. Equal in perimeter
  • D. None of these

3. All _______ triangles are similar.

  • A. Isosceles
  • B. Scalene
  • C. Equilateral
  • D. Right-angled

4. Basic Proportionality Theorem is also known as:

  • A. Pythagoras Theorem
  • B. Thales Theorem
  • C. Euclid's Lemma
  • D. Apollonius Theorem

5. In ΔABC, DE || BC such that AD = 1.5 cm, DB = 3 cm, and AE = 1 cm. What is EC?

  • A. 1.5 cm
  • B. 2 cm
  • C. 2.5 cm
  • D. 3 cm

6. If two triangles are similar, then their corresponding sides are:

  • A. Equal
  • B. Proportional
  • C. Parallel
  • D. Perpendicular

7. If ΔABC ~ ΔPQR, then which of the following is true?

  • A. AB/PQ = BC/QR = AC/PR
  • B. AB/QR = BC/PR = AC/PQ
  • C. AB/PR = BC/PQ = AC/QR
  • D. AB = PQ

8. Which of the following is NOT a criterion for similarity of two triangles?

  • A. AAA
  • B. SAS
  • C. SSS
  • D. RHS

9. In ΔABC, DE || BC. If AD/DB = 3/5 and AC = 5.6 cm, then AE is equal to:

  • A. 2.1 cm
  • B. 3.1 cm
  • C. 1.8 cm
  • D. 2.4 cm

10. If ΔABC ~ ΔDEF such that AB = 1.2 cm and DE = 1.4 cm, the ratio of areas of ΔABC and ΔDEF is:

  • A. 6 : 7
  • B. 36 : 49
  • C. 16 : 25
  • D. 9 : 16

11. In a right triangle ABC, right angled at B, if AC = 10 cm and AB = 6 cm, then BC is:

  • A. 8 cm
  • B. 7 cm
  • C. 9 cm
  • D. 4 cm

12. The length of hypotenuse of an isosceles right-angled triangle whose one side is 4 cm long is:

  • A. 4 cm
  • B. 4√2 cm
  • C. 8 cm
  • D. 2√2 cm

13. In ΔABC, AB = 6√3 cm, AC = 12 cm, and BC = 6 cm. The angle B is:

  • A. 120°
  • B. 60°
  • C. 90°
  • D. 45°

14. The line segment joining the midpoints of two sides of a triangle is parallel to the third side and equal to ____ of it.

  • A. Double
  • B. Half
  • C. One-third
  • D. Equal

15. Diagonals of a trapezium ABCD with AB || DC intersect each other at O. If AB = 2 CD, then ratio of areas of ΔAOB and ΔCOD is:

  • A. 1 : 4
  • B. 4 : 1
  • C. 2 : 1
  • D. 1 : 2

16. If a vertical pole of length 6 m casts a shadow 4 m long on ground, and at the same time a tower casts a shadow 28 m long, height of tower is:

  • A. 40 m
  • B. 42 m
  • C. 38 m
  • D. 50 m

17. Altitude of an equilateral triangle of side 8 cm is:

  • A. 4√3 cm
  • B. 2√3 cm
  • C. 8√3 cm
  • D. 4 cm

18. Areas of two similar triangles are in the ratio 9 : 25. The ratio of their corresponding sides is:

  • A. 81 : 625
  • B. 3 : 5
  • C. 5 : 3
  • D. 9 : 25

19. In ΔABC, ∠A = 90° and AD ⊥ BC. Then AD² is equal to:

  • A. BD × CD
  • B. AB × AC
  • C. BC × CD
  • D. AB × BD

20. Two triangles are similar if their corresponding angles are:

  • A. Equal
  • B. Unequal
  • C. Complementary
  • D. Supplementary

21. If side of an equilateral triangle is 'a', its area is given by:

  • A. (√3/4) a²
  • B. (√3/2) a²
  • C. (1/2) a²
  • D. √3 a²

22. Perimeters of two similar triangles ΔABC and ΔPQR are 36 cm and 24 cm respectively. If PQ = 10 cm, then AB is:

  • A. 15 cm
  • B. 12 cm
  • C. 18 cm
  • D. 20 cm

23. In a square ABCD, length of diagonal AC is 10 cm. The side of square is:

  • A. 5 cm
  • B. 5√2 cm
  • C. 10√2 cm
  • D. 5/2 cm

24. If ΔABC ~ ΔDEF and ∠A = 47°, ∠E = 83°, then ∠C is equal to:

  • A. 50°
  • B. 60°
  • C. 70°
  • D. 80°

25. A guy wire attached to a vertical pole of height 18 m is 24 m long and has a stake attached to other end. How far from base of pole should stake be driven?

  • A. 6√7 m
  • B. 12 m
  • C. 6√5 m
  • D. 18 m

26. Corresponding medians of two similar triangles are in ratio 4 : 9. Ratio of areas of these triangles is:

  • A. 2 : 3
  • B. 16 : 81
  • C. 81 : 16
  • D. 4 : 9

27. In a rhombus ABCD, side AB = 10 cm and diagonal AC = 12 cm. Length of other diagonal BD is:

  • A. 16 cm
  • B. 8 cm
  • C. 20 cm
  • D. 12 cm

28. If a line divides any two sides of a triangle in the same ratio, then the line is _____ to the third side.

  • A. Perpendicular
  • B. Parallel
  • C. Equal
  • D. Coincident

29. In ΔABC, D and E are points on AB and AC such that DE || BC. If AD = x, DB = x - 2, AE = x + 2, EC = x - 1, then x =

  • A. 4
  • B. 3
  • C. 2
  • D. 1

30. Triangle ABC is an isosceles triangle right-angled at C. Then AB² is equal to:

  • A. 2 AC²
  • B. AC²
  • C. 3 AC²
  • D. 4 AC²

How to use these MCQs

This page contains a chapter-wise objective practice set. Try the questions without checking the answer first, then use the explanation to understand the point you missed. The current page contains 30 questions, so you can practise in smaller sets when you are revising.

Quick revision tip

After the practice set, write down the question numbers you missed and revise only those concepts once more. This makes MCQ practice more useful than repeatedly attempting the same questions without reviewing mistakes.

More for this chapter

Class 10 › Mathematics › Triangles
Chapter notesRead the chapterPractice MCQsCheck what you rememberChapter test10 questions on one pageOnline testTest 1, 2 and 3, one question at a timePYQPrevious year questionsStudy materialPDF notes
Topics in this chapter: Similar TrianglesBasic Proportionality Theorem (Thales Theorem)Areas of Similar TrianglesPythagoras Theorem