Find the surface area of a closed cylinder when the height is three times the radius using only variables the answer is

of prism is 10 cm , can you help me to find the wide of prism

rstand how to find Surface Area and Volume of the shapes

have done the calculus which reveals that the surface area is at a minimum when height is double the radius. I am now trying to find an equation for the relationship between the amount of wasted surface area as a percentage of the minimum surface area and the ratio between height and radius. If I were to plot it on a graph, the y axis would be the percentage of excess materials needed as a percentage of the minimum possible surface area, and the x axis would be height divided by radius. Since the surface area is minimized when height=2(radius), I know that when x=2, y=0. The website https://www.datagenetics.com/blog/august12014/index.html explains what I am trying to do quite well and shows the graph below. I am trying to find the equation for this graph, but am unsure how to go about it.

variables). The answer is 8 pi r squared - 10pi r, but I'm not sure how they got the 10 pi r I only was able to get 8 pi r squared

find the surface area when the radius is 3 in.