To calculate the are of the sides of a cylinder, you take the circumference of the base, or circle, and multiply it times the height. To calculate the circumference of a circle we use the formula 2*pi*r, or 15pi. We multiply this times 20 to get 300pi cm. If you are using 3.14 for pi, this is 942, or if you are using actual pi, around 942.4777.
We know the equation for company A is P(t) = 1.8(1.4)ᵗ.
and what we know about company B is that their equation is linear, and we also have 3 months in a table of values, and we can simply use two points from there to get the equation of company B, let's do so using (3,5) and (7, 25),

now, the end of the year will be at the twelfth month, namely t = 12, and the four month well we know that t = 4.
how did each one fare?

so, notice, on the fourth month B did better than A, but at the end of the year, A ended up better off than B.
This transformation is called a rotation.