<span>Simplifying
X + 12 = 30
Reorder the terms:
12 + X = 30
Solving
12 + X = 30
Solving for variable 'X'.
Move all terms containing X to the left, all other terms to the right.
Add '-12' to each side of the equation.
12 + -12 + X = 30 + -12
Combine like terms: 12 + -12 = 0
0 + X = 30 + -12
X = 30 + -12
Combine like terms: 30 + -12 = 18
X = 18
Simplifying
X = 18</span>
<u><em>780 students</em></u>
<u><em></em></u>
<em>Set up a proportion.</em>
<em />
<em>75 / 125 = x/1300</em>
<em />
<em>125 10.4 = 1300</em>
<em />
<em>75 * 10.4 = 780</em>
<em />
<em>x=780</em>
ANSWER

EXPLANATION
The volume of a rectangular prism is given by the formula,

We substitute the dimensions to obtain,

The volume of the rectangular pyramid is,

Equating the two volumes gives,

We divide through by 6×12 to get,

We solve for x to obtain,

Answer:
<h2>B. 49,062.5 ft²</h2>
Step-by-step explanation:
The formula of an area of a circle:

r - radius
We have the diameter d = 250 ft. We know: d = 2r.
Therefore r = 250 : 2 = 125 ft.
Substitute:

