Question

The measure of interior angle of quadilateral are an APwith common difference 20 .find the measure of each angle?

Answer 1

 Quadrilateral had a total angle of 360 degrees 

So, The total of 4 terms is 360. 

Let the 4 angles be a, a+d, a+2d, a+3d as they are in a.p.... 
we say, a+(a+d)+(a+2d)+(a+3d)=360 => 4a+6d=360 
Given that d=20 
So, 4a+6*20=360 
4a=360-120 
4a=240 
=>a=60
so the angles would be likewise