Ok. Since you're doing volume, you've given me the height which is 11 and what I'm assuming to be the radius which is 14. the formula for a volume of a cylinder is v=pi(r^2)(h) so we plug it in (if the radius is 14)
V=π(14^2)(11)
V=π(196)(11)
V≈6773.27
By the way, this is what i was talking about with the line segment. Look at r (the radius). Usually when they show a diagram for a cylinder they include the radius, either at the top or the bottom as a line segment that goes through the circle at about halfway
2 represents the two kids, he is paying double the amount because two kids are enrolled. The 21 is the monthy charge and x is the number of months in class which 21x is the slope. 75 is a one time fee and is the y intercept.