Homework Help

This is what I got and I feel it is right but I am not so sure, please help me on this

Since triangles CBD  and  CAD  are on the same base (CD)...then their areas are to each other as their heights

So  

[ CAD ] / [ CBD ]  =  12 / 7

So

[ CAD ]  = (12/7) [ CBD ]

So

[ CBDA ] + [CBD ]  =  [ CAD ]

15   +   [CBD ]  =  (12/7) [ CBD ]

15  =  (12/7) [ CBD ] - [CBD ]

15  =  (12/7) [CBD ] - (7/7)[CBD]

15 = (5/7) [CBD ]

(7/5)(15)  = CBD

21  =  CBD

But  CAD  =  (12/7) [ CBD ]  = (12/7) (21) =  12 * 3  = 36  = [CDA]

You are correct  !!!

Thank you so much. I keep cross checking my work so much and I keep feeling that my answer is wrong, so I keep checking my work like this every single time