For this case we have that by definition, the volume of a rectangular prism is given by:

Where:
It is the area of the base of the prism
h: It is the height

Where:
w: is the width
l: is the length
According to the data of the statement we have:

Substituting the data we have:

We choose the positive value: 
So the height is
Answer:

Answer:
increase = 37.38 cm²
You'd like the first way because it took less effort and less chance of a miscalculation.
Step-by-step explanation:
first way:
(just work with the difference in height)
(0.7 x 8.7 x 2) + (0.7 x 18 x 2) = 37.38 cm²
second way:
old total lateral surface area = (31 x 8.7 x 2) + (31 x 18 x 2) = 1655.4
new total lateral surface area = (31.7 x 8.7 x 2) + (31.7 x 18 x 2) = 1692.78
increase = 1692.78 - 1655.4 = 37.38 cm²
- Calculating the area of a soccer field, Calculate area of _______
- Calculate the average height of everyone in your family
I think that the fencing is needed
I found the complete problem.
If Alice divides it into two trapezoids, the area formula would be: A = [(a+b) / 2] * h
Trapezoid 1
A = [(7.5 + 15)/2 * 5
A = (22.5/2) * 5
A = 11.25 * 5
A = 56.25 sq. ft
Trapezoid 2
A = [(5 + 10)/2 * 7.5
A = (15/2) * 7.5
A = 7.5 * 7.5
A = 56.25 sq. ft
Total area = 56.25 + 56.25 = 112.50 sq. ft.