Question 260448
Remember that the definition of a rectangle is a quadrilateral which has 4 right angles (ie 4 ninety degree angles). Because these lines intersect at the vertices, and the intersections form 90 degree angles, the lines are perpendicular at the vertices. Also, remember that perpendicular slopes are negative reciprocals of one another. For example, if you have a slope of {{{1/2}}}, the perpendicular slope is {{{-2/1=-2}}}