NCERT Solutions for Class 8 Maths Chapter 3 Understanding Quadrilaterals Exercise 3.3

Examples From Chapter 3 Understanding Quadrilaterals

Ex. 1 If each interior angle of a regular polygon is 158^o,  can it be an interior angle of a regular polygon? Give reason.

Soln: No, this is not true. Each exterior angles 180° – 22° = 158°, which is not a divisor of 360°.

Ex. 2 Find the angle measure x in the following figure.

Soln: 

x + 30° + x + (180° – 70°) + (180° – 60°) = (5 – 2) × 180° [ angle sum property of a pentagon]
∴ 2x + 30° + 110° + 120° = 540°
∴ 2x + 260° = 540°
∴ 2x = 540° – 260°
∴ 2x = 280°
∴ x=280^∘/2
∴ x = 140°