The angle of depression from d to f measures 25°. if ef = 10 yd, find de. round your answer to the nearest tenth.

This question needs more information like where point E is but I'm going to assume that point E is directly below point D

With that assumption, angle EDF should be (90°- 25°) which is 65°

tan 65° = opposite/adjacent
tan 65° = 10 yd/ DE
DE = 10 yd/tan 65°
DE = 4.7 yd (to the nearest tenth)

Remember to include a picture next time for greater clarity :)