The area covered by a city is 20 square miles. The area grows by a factor of 1.1 each year since it was 20 square miles. Explain why the area, `a`, covered by the city, in square miles, is a function of `t`, the number of years since its area was 20 square miles.

Technicians have installed a center pivot, circular irrigator for a farm that covers 25 acres. a.) how long is the irrigation boom (in feet) from the center pivot to its farthest extent? b.) if the irrigation boom makes 4 full revolutions in a day, how many miles does the end of the boom travel in 5 days?