Please Help easy question in Geometry 10 points best answer

please help I can a test tomorrow and I need someone to explain this to me.

In a triangle ABC, D is a point on AC and E is a point on BC such that DE parallel to AB. If DE=8, AB=20, CD=4, EB=9.
E and D has a horizontal line going connecting them
Find:
a,) CA
b.) CE
c.) AD

Thank you to everyone who helps out

Since AB || DE, the triangle CDE is similar to ABC. Its sides are 8/20 or 2/5 the corresponding sides of ABC. That means:

1) (AD + DC) * 2/5 = DC
(AD + 4) * 2/5 = 4
(AD + 4) = 10
AD = 6

2) (EB + CE) * 2/5 = CE
(9 + CE) * 2/5 = CE
(9 + CE) * 2 = 5*CE
18 + 2*CE = 5 * CE
18 = 3 * CE
CE = 6

a) CA = 10
b) CE = 6
c) AD = 6

C