Question

a quadrilateral has one angle equal to 120 degree and it's other 3 angles are equal . the measure of the equal angles is

a. 40 degree
b. 60 degree
c. 80 degree
d. 100 degree ​

Answer 1

80 is the answer
total angles in a quadrillatral is 360 one is 120 then other three sum is 240
divide thus 240 with 3 we get 80

Answer 2

Let the 3 angle be x

As we know the sum of angle of a quadrilateral= 360

120+x+x+x=360

120+3x=360

3x=360-120

3x=240

x=240/3

x=80