Working out the hypotenuse

Question

Work out the length of the line {BR}, correct to {1} decimal place.

Right-angled triangle BPR

BR^2 = 4^2 + 7^2

BR^2 = 16 + 49

BR^2 = 65

{BR}=\sqrt65 (Find the square root of both sides)

BR={8.1~cm} ( {1} decimal place)