With 7a and 7b. the picture above is irrelevant to the problem. if possible explain or show your work.

If the ratio is 4:3  divide the larger can by 4  which in a)  is  25 then multiply by 3 to get surface area of smaller can which would be 75 square inches. 

In part b) do the same so 150 divided by 4 is 37.5  multiplied by 3  is 112.5 cubic inches.

It doesn't matter if it is surface area or volume you still use the same ratio of 4:3

step-by-step explanation:

graph using a few selected

x         y

-1       15

0         6

1         2.4

2       0.96