## Elementary Geometry for College Students (6th Edition)

Using the Pythagorean Theorem... $a^{2}+b^{2}=c^{2}$ $3^{2}+8^{2}=15^{2}$ Simplify... $9+64=225$ $73=225$ Since the sum of the sides squared $(73)$ is less than the hypotenuse squared $(225)$, the triangle is an obtuse triangle.