Answer:
ED = 8
Step-by-step explanation:
ΔAED ~ ΔDEC so the corresponding sides are in proportion:
DE/DC = AE/AD
(x+4)/6 = (2x +4)/9
3(x +4) = 2(2x +4) . . . . multiply by 18
3x + 12 = 4x +8 . . . . . . eliminate parentheses
4 = x . . . . . . . . . . . . . . . add -8-3x
ED = x +4 = 4 +4
ED = 8
