A rectangle has a length of 1 inches and a width of 12 inches whose sides are changing. The length is decreasing by 6 in/sec and the width is shrinking at 2 in/sec.
What is the rate of change of the perimeter?

If the angle bisectors of a pair of opposite angles of a quadrilateral are the opposite sides of a parallelogram formed by the two angle bisectors and two sides of the quadrilateral, is the quadrilateral always a parallelogram? explain your answer.