I think this video will help you so much, it's about how to solve it from Khan Academy
https://www.khanacademy.org/math/pre-algebra/pre-algebra-exponents-radicals/pre-algebra-scientific-notation/v/scientific-notation-old
Answer:
B
Step-by-step explanation:
The volume (V) of the prism is calculate as
V = lbh ( l is the length, b the width and h the height )
l = h = 4 ×
= 
b = 3 ×
= 1, thus
V =
× 1 ×
=
ft³
The maximum area of the pen is the highest area the pen can have
The maximum area is 16200 square yards
Let the dimension be x and y.
So, the perimeter is given as:

Because it has one additional fence, the perimeter is calculated as:

Make y the subject

The area is calculated as:

Substitute 

Expand

Differentiate

Set to 0

Rewrite as:

Divide both sides by 4

Substitute 90 for x in 


Hence, the maximum area is 16200 square yards
Read more about maximum areas at:
brainly.com/question/11906003