Question

How do I solve this ?

Answer 1

Look at the picture.

ΔZYX and ΔDYC are similar. Therefore the lengths of sides are in proportion:

`(DC)/(ZX)=(DY)/(ZY)`

DC = x

ZX = 16

DY = a

ZY = a + a = 2a

Substitute:

`(x)/(16)=(a)/(2a)`

`(x)/(16)=(1)/(2)` multiply both sides by 16

`\boxed{x=8}`

Answer: CD = 8