Pythagorean theorem 12^2 + b^2=27^2

Solve for b over the real numbers:

b^2 + 12^2 = 27^2

b^2 + 12^2 = b^2 + 144 and 27^2 = 729:

b^2 + 144 = 729

Subtract 144 from both sides:

b^2 = 585

Take the square root of both sides:

Answer: b = 3 sqrt (65) or b = - 3 sqrt (65)