Question

what are the values of a and b

Answer 1

You could set up the #'s that the sides to an equation like the Pythagorean Theorem.. and then solve for each variable
If that makes sense

Answer 2

There's a special relationship btw the right triangles in this diagram

So 6= sqrt of 8a
And you try to solve for a.

Once you find a
b is

b=sqrt of a times 8+a