Figuring the sum of a square.....homework help.?

Question

There are four children in a family. The sum of the squares of the ages of the three youngest children equals the square of the age of the oldest child. How old are the children?
A.1,4,8,9
B1,3,6,12
C.4,5,8,10
D. 2,3,8,16

Show the work if you can.

Answer 1

The easiest way is to try each case of A, B, C, and D.
A: 1^2 + 4^2 + 8^2 = 1 + 16 + 64 = 81 = 9^2 is the answer.