The picture shows the two squares. The squares create 4 identical triangles with lengths of 3, b, and 4. To find b we can just use pythagorean theorum. 3^2 + b^2 = 4^2. So 9 + b^2 =16. to find b subract 9 from 16. b^2 = 16-9. That comes out to 7 so, b^2 = 7. That means the b is equal to the square root of 7.
