## College Algebra (11th Edition)

The distance between A and B: $$\sqrt{(-4-2)^2+(3-5)^2}$$ $$\sqrt{36+4}$$ $$\sqrt{40}$$ The distance between B and C: $$\sqrt{(2-(-1))^2+(5-(-6))^2}$$ $$\sqrt{9+121}$$ $$\sqrt{130}$$ The distance between A and c: $$\sqrt{(-4-(-1))^2+(3-(-6))^2}$$ $$\sqrt{9+81}$$ $$\sqrt{90}$$ Use the Pythagorean Theorem to test if this is a right triangle. $$40+90=130$$ $$130=130$$ Yes, this is a right triangle.