9303753286127016 Class 9 Maths Chapter 7 Triangles MCQs

Class 9 Maths Chapter 7 Triangles MCQs

Class 9 Maths Chapter 7 Triangles MCQs

Class 9 Maths Chapter 7 (Triangles) MCQs are provided here with answers, online. Students can practice these objective questions to score good marks in the final exam (2020-2021). All the problems here are based on the CBSE syllabus and NCERT curriculum. A detailed explanation is given for each question to help students understand the concepts. Learn chapter-wise MCQs. Also, check Important Questions for Class 9 Maths.

MCQs on Class 9 Triangles

Solve the MCQs given below and choose the correct answer among the four options. Match your answers with the given answers here.


1) In triangle ABC, if AB=BC and ∠B = 70°, ∠A will be:

a. 70°

b. 110°

c. 55°

d. 130°

Answer: c

Explanation: Given,

AB = BC

Hence, ∠A=∠C

And ∠B = 70°

By angle sum property of triangle we know:

∠A+∠B+∠C = 180°

2∠A+∠B=180°

2∠A = 180-∠B = 180-70 = 110°

∠A = 55°

2) For two triangles, if two angles and the included side of one triangle are equal to two angles and the included side of another triangle. Then the congruency rule is:



a. SSS

b. ASA

c. SAS

d. None of the above

Answer: b

3) A triangle in which two sides are equal is called:

a. Scalene triangle

b. Equilateral triangle

c. Isosceles triangle

d. None of the above

Answer: c

4) The angles opposite to equal sides of a triangle are:

a. Equal

b. Unequal

c. supplementary angles

d. Complementary angles

Answer: a

5) If E and F are the midpoints of equal sides AB and AC of a triangle ABC. Then:

a. BF=AC

b. BF=AF

c. CE=AB

d. BF = CE

Answer: d

Explanation: AB and AC are equal sides.

AB = AC (Given)

∠A = ∠A (Common angle)

AE = AF (Halves of equal sides)

∆ ABF ≅ ∆ ACE (By SAS rule)

Hence, BF = CE (CPCT)

6) ABC is an isosceles triangle in which altitudes BE and CF are drawn to equal sides AC and AB respectively. Then:

a. BE>CF

b. BE<CF

c. BE=CF

d. None of the above

Answer: c

Explanation:

∠A = ∠A (common arm)

∠AEB = ∠AFC (Right angles)

AB = AC (Given)

∴ ΔAEB ≅ ΔAFC

Hence, BE = CF (by CPCT)

7) If ABC and DBC are two isosceles triangles on the same base BC. Then:

a. ∠ABD = ∠ACD

b. ∠ABD > ∠ACD

c. ∠ABD < ∠ACD

d. None of the above

Answer: a

Explanation: AD = AD (Common arm)

AB = AC (Sides of isosceles triangle)

BD = CD (Sides of isosceles triangle)

So, ΔABD ≅ ΔACD.

∴ ∠ABD = ∠ACD (By CPCT)

8) If ABC is an equilateral triangle, then each angle equals to:

a. 90°

B.180°

c. 120°

d. 60°

Answer: d

Explanation: Equilateral triangle has all its sides equal and each angle measures 60°.

AB= BC = AC (All sides are equal)

Hence, ∠A = ∠B = ∠C (Opposite angles of equal sides)

Also, we know that,

∠A + ∠B + ∠C = 180°

⇒ 3∠A = 180°

⇒ ∠A = 60°

∴ ∠A = ∠B = ∠C = 60°

9) If AD is an altitude of an isosceles triangle ABC in which AB = AC. Then:

a. BD=CD

b. BD>CD

c. BD<CD

d. None of the above

Answer: a

Explanation: In ΔABD and ΔACD,

∠ADB = ∠ADC = 90°

AB = AC (Given)

AD = AD (Common)

∴ ΔABD ≅ ΔACD (By RHS congruence condition)

BD = CD (By CPCT)

10) In a right triangle, the longest side is:

a. Perpendicular

b. Hypotenuse

c. Base

d. None of the above

Answer: b

Explanation: In triangle ABC, right-angled at B.

∠B = 90

By angle sum property, we know:

∠A + ∠B + ∠C = 180

Hence, ∠A + ∠C = 90

So, ∠B is the largest angle.

Therefore, the side (hypotenuse) opposite to largest angle will be longest one.

Balkishan Agrawal

At the helm of GMS Learning is Principal Balkishan Agrawal, a dedicated and experienced educationist. Under his able guidance, our school has flourished academically and has achieved remarkable milestones in various fields. Principal Agrawal’s vision for the school is centered on providing a nurturing environment where every student can thrive, learn, and grow.

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