Assume the 3rd side is the hypotenuse:
a² + b² = c²
c² = 12² + 15²
c² = 369
c = √369
c = 19.21 inches (nearest hundredth)
Assume the 3rd side is not the hypotenuse:
a² + b² = c²
12² + b² = 15²
b² = 15² - 12²
b² = 81
b = √81
b = 9 inches
Difference between the two length:
19.21 - 9 = 10.21 inches
Answer: 10.21 inches
