Question

After joining two pieces of a picture frame together, a frame maker checks her work by measuring the diagonal (see the illustration). The sides of the frame form a right angle and the measurements are as follows: a = 12 in. and b = 5 in.

Answer 1

The diagonal (hypotenuse) is 13 in.

You need to use the Pythagorean Theorem

${a}^{2} + {b}^{2} = {c}^{2}$
then just plug in the numbers and solve for c.

${12}^{2} + {5}^{2} = {c}^{2}$
$\sqrt{169} = c$
13 = c