So considering she’s using the Pythagorean Theorem, it implies that it’s a right triangle. In this case, a^2+b^2=c^2 is used to solve for any length. While “a” and “b” are interchangeable, c is always the hypotenuse. And as you may know, the hypotenuse is the longer side of the right triangle.
So now solve for it to be sure if it is in fact a right triangle.
8^2+15^2=17^2
64+225= 289
289=289
Which means B is the error made.
Hope this helps!
