Three angles of a quadrilateral are respectively equal to 110°, 50° and 40°. Find its fourth angle.

Given,

Three angles are 110^°, 50^° and 40^°

Let the fourth angle be 'x'

We have,

Sum of all angles of a quadrilateral = 360^°

110^° + 50^° + 40^° = 360^°

⟹ x = 360^° - 200^°

⟹ x = 160^°

Therefore, the required fourth angle is 160^°.