9514 1404 393
Answer:
y = 15
Explanation:
Triangle ABC is similar to triangle DEC, so corresponding segments are proportional.
EB/DA = CB/CA . . . . . . . . . a proportion involving corresponding segments
y/20 = 21/28 . . . . . . . . . . . . with numbers filled in
y = 20(21/28) = 20(3/4) . . . multiply by 20 to find y
y = 15