a) A computer is an expanding circular pattern. The circle starts as a dot, then expands outwards as it grows over time. With a 21" screen, you have...

a) A computer is an expanding circular pattern. The circle starts as a dot, then expands outwards as it grows over time. With a 21" screen, you have a viewing area with a 10" radius. The screen reaches the corners in exactly 4 seconds. Express the radius of the circle as a function of time. b) The cost of fuel in C dollars is a function of the number of liters (L) of fuel consumed. The cost of fuel is $1.01 per litre. The amount of fuel consumed (L) is a functions of the number of hundred of km (K) travelled. A car consumed 12.4 L per 100 km. If you spend $112.72 on gas, how long was the trip?