Question

.A quadrilateral has three acute angles, each measure 80.What is the measure of the fourth angle?

Answer 1

80+80+80+fourth angle=360
240+fourth angle=360
fourth angle=360-240
fourth angle=120

Answer 2

we know that interior angle of a quad. = 360 degree
then,
let forth angle be x
A/Q
=> 80+80+80+x = 360
=> 240+x = 360
=> x = 360-240
=> x = 120
our forth angle is 120 degree