Question

in quadrilateral abcd , angle A=57 degrees , angle B=65 degrees and angle c=118 degrees What is the measure of an exterior angle at D

Answer 1

The total measure of the interior angles of a quadrilateral is 360 degrees
you are given 57, 65, 118
That is 240
to solve for the last angle
360-240
120
The exterior angle of a D would be the number that you add that will make it 180 degrees.
meaning 180-120 is
The exterior angle of angle D is 60 degrees.

Hope this helps