The vertices of a triangle are a(5, –4), b(7, 0), and c(1, –2). if the triangle is a right triangle, which vertex is the right angle?

Sean is his dad build a tiled walkway in their backyard. the walkway will be 6060 feet long and 22 feet wide. the local hardware store sells tiles which are 22 by 22 feet and come in boxes of 66. how many boxes of tiles do they need?