Find the missing coordinate r, given the slope. 19) (12, 10) and (2, r) m = 20) (-11, r) and (12, 5); m = 0 Calculate Using the Slope formula and cross- multiplication 2 - 1 m 3D 21) (-4,9) and (r, -6); m 0 22) (r, 6) and (-7, -4); m = 2 23) (r, 9) and (-11,-1); m= 24) (3.r) and (1, 10) m=1 112