The sum of squares of three numbers is 280. If the numbers are in the ratio 3:5:6, find the greatest number.

A. 8
B. 6
C. 12
D. 18
Let the numbers be 3x,5x and 6x. (3x)²+(5x)²+(6x)²=280 9x²+25x²+36x²=280 70x²=280 x²=4 x=2 The greatest number is 6x=12.