Answer:
Rate of change = 3π or 9.43
Explanation:
Given the following data;
Initial radius, R1 = 4 inches
Final radius, R2 = 12 inches
To find the rate of change;
First of all, we would determine the area of the circle.
Mathematically, the area of a circle is given by the formula;
Area of circle = πr²
For initial radius, R1;
Area of circle, A1 = πR1²
Area of circle, A1 = 4π square inches
For final radius, R2;
Area of circle, A2 = πR2²
Area of circle, A2 = 12π square inches
Now, we can find the rate of change;
Rate of change = A2/A1
Rate of change = 12π/4π
Rate of change = 3π (in terms of pie).