What is the diagonal of a 9 in x 12 in rectangle?

Answer 1

recall the Pythagorean Theorem.

d^2 = 9^2 + 12^2 = 81+144 = 225
do, d=15

Also, it helps to recall a few simple and commonly used right triangles. The most basic is

3-4-5

Your 9-12-15 triangle is just a 3-4-5 scaled up by a factor of 3.

Answer 2

Thanks!