What is the sum of lengths of the two diagonals in a rectangle 5 by 12?

A. 25

B. 26

C. 144

D. 169

First we must calculate the diagonal of the rectangle. To do this we must use Pythagoras' Theorem: c^2 = a^2 + b^2, where c^2 is the diagonal and a^2 and b^2 are the length and width of the rectangle.

So we have:

c^2 = 5^2 + 12^2

c^2 = 169

c = 13

The lengths of the two diagonals in a rectangle are equal, therefor the sum of the lengths would be 13*2 = 26