Question

An angle of a parallelogram is half of its adjacent angle. The smallest angle of a quadrilateral is ______.

Options

• 30°

• 80°

• 45°

• 60°

Answer 1

An angle of a parallelogram is half of its adjacent angle. The smallest angle of a quadrilateral is 60°.

Explanation:

Let the smaller adjacent angle be x and the other be 2x, since one is half the adjacent angle. 

Adjacent angles of a parallelogram sum to 180°.

So, x + 2x = 180°

⇒ 3x = 180°

⇒ x = 60°