Question

Can someone help me with this? (quick please!)

Answer 1

The squares have a triangle in between them. The red square forms the hypotenuse, so we can use the Pythagorean theorem.

n^2 = 9^2 + 12^2

n^2 = 81 + 144

n^2 = 225

n = 15

There's your answer :)

n = 15