Show that the points A, B and C below are the vertices of a right triangle. (Hint: Apply
the distance formula and the Pythagorean Theorem. Pythagorean Theorem: If the sum of
the squares of the lengths of two sides of a triangle is equal to the square of the length of
the third side, then the triangle is a right triangle.)
(−3,1), (2, −1), (6,9)