Use the Pythagorean Theorem: a² + b² = c².
a and b are the legs of the right triangle, and c is the hypotenuse.
2) 5² + b² = 6²
25 + b² = 36
b² = 11
b = 3.3 cm
3) 7² + b² = 8²
49 + b² = 64
b² = 15
b = 3.9 cm
4) a² + 5² = 13²
a² + 25 = 169
a² = 144
a = 12 cm