Hey could I get some help plz.

Since ABC is isosceles, its altitude will  bisect BC.....  and can be found as :  

sqrt ( 50^2 - 14^2)  =  sqrt (2304) = 48

So......call the intersection point of the altitude  and BC, E

So  ED  =

sqrt (52^2 - 48^2 )  = sqrt (400)  = 20

And    CD  =  ED - (1/2)BC   =   20 - 14   =   6 units