sum = 180(n-2) degrees
since pentagon has 5 sides (n=5)
sum of all the angles=180(5-2)=180*3 = 540 degrees
given four of the angles measure 30,60,120, and 165
let the fifth angle be x
so 30+60+120+165+x=540 => 375+x=540
thus x=165 degrees
so the fifth angle measures 165 degrees