The height will be four, becaus 5 is the height of the base not the whole prism. You can tell be beacause when you find the area of the base and multiply it by the height you multiply it by 4 not 5.
Just use the formula y=mx+b and you should get your answer

Above step we use "Multiplication property of equality"

In the above step we "Simplify on both sides of equation"

In the above step we use "Distribution property"

The above step is the result of using "Subtraction property of equality"

Above step is result of "Combining the like terms"

Above step is the result of using "Division property of equality"

Above step is result of "Simplifying fractions on either side of equation"
The change from 10 to 11 or from 100 to 101 is 1 in each case.
In the first case, the percentage of change is 1/10 = 10%.
In the second case, the percentage of change is 1/100 = 1%.
The percentages of change are different because the bases from which the change is measure are different.