Take the square root of the quantity R^2 + Y^2 + B^2 minus the quantity R(Y) + R(B) + B(Y).
R^2 = R squared
(900 + 625 + 1600) - (750 + 1200 + 1000)
3125 - 2950
175 Square rood of 175 = 13.2288

Don

Don(resqcapt19)