Determining if a triangle is a right triangle with given vertices

Question

Given are the vertices (corners) of triangles. Use the distance formulas to determine if each triangle is a right triangle.
a. (-2,5), (0, -1), (12, 3)
b. (2, 3), (-2, -3), (-6, 1)
c. (-3, -2), (5, -2), (1, 2)

 

I know we are using the distances formula but I'm slightly confused as to how so exactly? 

Answer 1

You have been given three points (in each of three problems).

 

Take two points at a time--and compute the distances in each of these three cases.

Then see if the square of the largest distance equals the sum of the squares of the other two distances; if so, you have aright triangle on your hands.