Sam cut a pie into equal slices. there are only three slices left. the angle measure for the three slices is 72°. how many slices did sam cut the pie into?

Sam cut the pie in 15 slices.

Since 3 slices is 72 degrees, that means each slice is 24 degrees.
The amount of slices can be determined by dividing the 360 degrees in a circle by the 24 degrees in a slice of pie, which is 15.

72/3=24°

So each slice was 24°

360/24=15

So originally there were 15 slices...

That is the answer to your question