Question

One angle of a quadrilateral is 90° and all other angles are equal ; find each equal angle.

Answer 1

Let the angles of a quadrilateral be x°,

x°, x° and 90°

∴ Sum of interior angles of quadrilateral = 360°

⇒ x° + x° + x° + 90° = 360°

⇒ 3x° = 360° - 90°

⇒ x = `(270°)/3`

⇒ x = 90°