Frank cut a pie into 10 equal slices. There are only 3 slices left. what is the measure of the angle for 3 slices that are left?

360/10x3

the angle of the whole pie (a circle) equals 360°. he cut it into 10 pieces so each piece degree measurement is 36 (360°/10) and then there are 3 slices so together that's 108° (36°x3)