a2 + (a + 49)2 = 912
a2 + a2 + 98a + 2401 = 8281
2a2 + 98a - 5880 = 0
a2 + 49a - 2940 = 0
(a + 84)(a - 35) = 0
a + 84 = 0
a = -84
We don't measure in negatives, so we disregard this answer.
a - 35 = 0
a = 35"
35 + 49 = 84"