The sum of exterior angles of any polygon will always equate to 360 degrees. Therefore, we can write:
360 = (x+10) + (2x+20) + <span>3x
Solving for x,
x = 55
The exterior angles will have values of 65, 130 and 165. The exterior that will have the largest value will correspond to the smallest interior angle and will have a value of 15 degrees.</span>