The monthly cost of a certain long distance service is given by the linear function c(t) = 0.06 + 3.95 where c(t) is in dollars and t is the amount of time in minutes called in a month. find the cost of calling long distance for 140 minutes in a month

a. $17.95
b. $11.35
c. $8.40
d. $12.35

You are standing next to a really big circular lake. you want to measure the diameter of the lake, but you don't want to have to swim across with a measuring tape! you decide to walk around the perimeter of the lake and measure its circumference, and find that it's 400\pi\text{ m}400? m. what is the diameter dd of the lake?