How would you figure out if a triangle with vertices (0,5), (1,2.5), and (-10,1) is a right triangle?
Prove right triangle
Call A(0, 5), B(1, 2.5) and C(-10, 1) the 3 points of the triangle.
Prove that the line AC is perpendicular to the line AB by showing that their slope product is (-1).
Slope of AC:
Slope of line AB:
The product ab = -1 . therefor, the 2 lines are perpendicular.