Find the value of the unknown exterior angle x in the following diagrams:

Solution:

We know that according to the exterior angle theorem, the exterior angle of a triangle is the sum of interior opposite angles.

By using this fact, we can find out the unknown exterior angle x.

(i) Interior angles are 50° and 70°

Exterior angle = sum of interior opposite angles

𝑥 = 50° + 70°

𝑥 = 120°

(ii) Interior angles are 65° and 45°

Exterior angle = sum of interior opposite angles

𝑥 = 65° + 45°

𝑥 = 110°

(iii) Interior angles are 30° and 70°

Exterior angle = sum of interior opposite angles

𝑥 = 30° + 40°

𝑥 = 70°

(iv) Interior angles are 60° and 60°

Exterior angle = sum of interior opposite angles

𝑥 = 60° + 60°

𝑥 = 120°

(v) Interior angles are 50° and 50°

Exterior angle = sum of interior opposite angles

𝑥 = 50° + 50°

𝑥 = 100°

(vi) Interior angles are 30° and 60°

Exterior angle = sum of interior opposite angles

𝑥 = 30° + 60°

𝑥 = 90°

☛ Check: NCERT Solutions Class 7 Maths Chapter 6

Video Solution:

Find the value of the unknown exterior angle x in the following diagrams:

NCERT Solutions for Class 7 Maths Chapter 6 Exercise 6.2 Question 1

Summary:

The value of the unknown exterior angle x in the following diagrams are: (i) 𝑥 = 120°, (ii) 𝑥 = 110°, (iii) 𝑥 = 70°, (iv) 𝑥 = 120°, (v) 𝑥 = 100°,(vi) 𝑥 = 90°

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