Tell whether the intersection of AB and CD form a right angle. A(7, 12), B(1,5), C(10,-7), D(3,-1)

The answer would be (c)

“exterior angles of triangles. an exterior (or external) angle is the angle between one side of a triangle and the extension of an adjacent side. try this drag the orange dots on any vertex to reshape the triangle.” look to get to the answer i explained what it means and other things i hope it you .