Slope as an (improper fraction)-9/7, it can’t be simplified
The way to get the equation for the radius (r) is to get r by itself. So divide each side by 4pi
500/4pi=r^2
Now take the square root of each side to get the equation of r.
sqrt(500/4pi)=r
The answer is C) 10x + 330 ≤ 600.
We use the ≤ since you are allowed to use the 600th minute.
When we subtract 330 from both sides, it makes a bit more sense
10x ≤ 270
270 is the number of minutes left your plan since you've already used 330, and you have 10 days left in the month.
2238 - 300 = 1938 ft is your answer