Question

if one of the angle of a quadrilateral of 120degree and the remainig three angles are equal, then the measure of each angle is

Answer 1

sum of all angles= 360
oneagle=120
sum of three equal angles=360-120=240
each angle =240/3=80 degrees

Answer 2

Since, the remaining three angles are equal so let they be 'x'.
As, we know that sum of all the angles of a quadrilateral is 360°.
⇒ x + x + x + 120° = 360
⇒            3x + 120 = 360
⇒                      3x = 360-120
⇒                      3x = 240
⇒                        x = 80°
∴ The angles of a quadrilateral are 80°, 80°, 80° and 120°.