A^2 + B^ = C^2
First solve the smaller triangle since we have both sides. I’m calling h the third side.
4^2 + 5^2 = h^2
16 + 25 = h^2
H^2 = 41 (take the square root)
H = 6.4
Now we use that number with the side = 6 the same way to get X.
6^2 + 6.4^2 = x^2
36 + 41 = x^2
77 = x^2 (take square root)
X = 8.8 (rounded up)
