3 The length of a rectangle is increasing at a rate of 3 cm s" and its width is decreasing at a rate of 3 cm s"). If the length and width of the rectangle are initially 24 cm and 7 cm respectively, find the initial rate of change of its a area; b perimeter; c diagonal. 4 A 10 m-long industrial ladder is leaning against a wall on a building site. The top of the ladder starts to slip down the wall at a rate of 0.5 m s . Determine how fast the foot of the ladder is moving along the ground when it is 6 m from the wall