125° + m = 180°

⇒ m = 180° – 125° = 55° (Linear pair)

125° + n = 180°

⇒ n = 180° – 125° = 55° (Linear pair)

x = m + n (exterior angle of a triangle is equal to the sum of 2 opposite interior 2 angles)

⇒ x = 55° + 55° = 110°

(b)  figure.png

Two interior angles are right angles = 90°

70° + m = 180°

⇒ m = 180° – 70° = 110° (Linear pair)

60° + n = 180°

⇒ n = 180° – 60° = 120° (Linear pair)

The figure is having five sides and is a pentagon.

Thus, sum of the angles of pentagon

= 540° 90° + 90° + 110° + 120° + y = 540°

⇒ 410° + y = 540°

⇒ y = 540° – 410° = 130°

x + y = 180° (Linear pair)

⇒ x + 130° = 180°

⇒ x = 180° – 130° = 50°