b. Determine the length of radius of the circular ripple after 3 seconds. A rock is thrown into a lake creating a circular ripple that gets larger over time. f(r) = ar" models the area (in cm²) enclosed by a circle with a radius of r cm. If the ripple's radius increases by 8 cm per second, then g(t) = 8t models the length of the circular ripple's radius (in cm) after t seconds. cm Preview c. What is the area enclosed by the circular ripple after 3 seconds? a. Use the following applet to explore this context. You can vary the time elapsed since the rock hit the lake's surface (values of t) using the given slider. cm2 Preview d. What is the area enclosed by the circular ripple after 5 seconds? t=0.50 cm? Preview e. What is the area enclosed by the circular ripple after 7 seconds? cm2 Preview f Which of the following represent the area enclosed by the circular ripple after t seconds? Select ALL that apply (there may be multiple equivalent ways to represent this value). fr 口x- 16t OR 6412 Or(81) 口ォ. 16t? 口ォ.8

The radius of a spherical balloon is increasing at a rate of 4 centimeters per minute. How fast is the surface area changing when the radius is 14 centimeters? Hint: The surface area is S = 4Tr2. Rate of change of surface area =