X = x 1 + ( x 2 − x 1 ) t , y = y 1 + ( y 2 − y 1 ) t where 0 ≤ t ≤ 1 describe the line segment that joins the points P 1 ( x 1 , y 1 ) and P 2 ( x 2 , y 2 ) . Use a graphing device to draw the triangle with vertices A ( 1 , 1 ) , B ( 4 , 4 ) , C ( 1 , 6 ) . Find the parametrization, including endpoints, and sketch to check. (Let x and y be in terms of t .)