Find the value of x° and y° from the following figures:

Theorem 2:

If a side of a triangle is produced, the exterior angle so formed, is equal to the sum of the two-interior angle.

Ext. ∠ B = ∠ A + ∠ C

⇒ y° = x° + 50° …(1)

Ext. ∠ B + 72° = 180°

⇒ Ext. ∠ B = 180° - 72°

⇒ Ext. ∠ B = 108°

⇒ y° = 108°

Put y = 108° in (1)

⇒ 108° = x° + 50°

⇒ x° = 108° - 50°

⇒ x° = 58°