The diagram shows that the one triangle can be divided into two equal right triangles. Because of this, you can use the Pythagorean Theorem to solve this problem. a and b are the two sides of the angles, and c is the hypotenuse.
The given lengths are 5 as the hypotenuse and 3 as one length. (You have 3 as a given length because the two triangles have a length of 6 on one side. 6/2 = 3)
