(a) A spherical iron ball 6 cm in diameter is coated with a layer of ice with uniform thickness. If the ice melts at a rate of 25 cm³/min how fast is the thickness of the ice decreasing when it is 4 cm thick? 4 (b) The altitude of an isosceles triangle is decreasing at a rate of 3 cm/min while its perimeter is increasing at a rate of 2 cm/min. How fast is each of the sides changing when the sides are a = 4 cm, b = 4 cm, and c = 6 cm?

A circle is inside a square. The radius of the circle is decreasing at a rate of 1 meter per minute and the sides of the square are decreasing at a rate of 3 meters per minute. When the radius is 3 meters, and the sides are 18 meters, then how fast is the AREA outside the circle but inside the square changing? The rate of change of the area enclosed between the circle and the square is square meters per minute.

A toy aircraft is flying East passing above a radar at a constant height of 30 feet from the ground and it casts a shadow on the ground that is moving at the rate of 10 feet per second. At what rate is the distance from the radar to the aircraft changing at the instance where toy aircraft is 50 feet away from the radar?