Question

Three angles of a quadrilateral are 75º, 90º and 75º. The fourth angle is ______.

Options

• 90º

• 95º

• 105º

• 120º

Answer 1

Three angles of a quadrilateral are 75º, 90º and 75º. The fourth angle is 120º.

Explanation:

Given: 3 angles of quadrilateral - 75°, 90° and 75°

Let the fourth angle be x.

We know that,

Sum of all angles of a quadrilateral = 360°

⇒ 75° + 90° + 75° + x = 360°

⇒ 240° + x = 360°

⇒ x = 360° – 240°

⇒ x = 120°