Solution
First we will label the triangle
In triangle ACD , we will use pythagoras theorem

In triangle ACB, Using pythagoras theorem

In triangle ABD , we will also use pythagoras theorem

Now we have three equations
Let us find a replacement for y^2 in the first equation
From equ(3),


Now we will find a replacement for z^2 in the new equation
We will recall that

We will substitute for z^2 in x^2=z^2 - 65
