The formula for the volume of a right circular cylinder is [tex]V=\pi r^2 h[/tex]. If [tex]r=2b[/tex] and [tex]h=5b+3[/tex], what is the volume of the cylinder in terms of [tex]b[/tex]?



Answer :

To determine the volume of the cylinder given the relationships involving [tex]\( b \)[/tex], let's proceed step-by-step.

1. Recall the formula for the volume of a cylinder:
[tex]\[ V = \pi r^2 h \][/tex]
where [tex]\( V \)[/tex] is the volume, [tex]\( r \)[/tex] is the radius, and [tex]\( h \)[/tex] is the height.

2. Substitute the expressions for [tex]\( r \)[/tex] and [tex]\( h \)[/tex]:
The radius [tex]\( r \)[/tex] is given by:
[tex]\[ r = 2b \][/tex]
The height [tex]\( h \)[/tex] is given by:
[tex]\[ h = 5b + 3 \][/tex]

3. Plug these values into the formula:
Substitute [tex]\( r = 2b \)[/tex] and [tex]\( h = 5b + 3 \)[/tex] into the volume formula:
[tex]\[ V = \pi (2b)^2 (5b + 3) \][/tex]

4. Simplify the expression:
First, calculate [tex]\( (2b)^2 \)[/tex]:
[tex]\[ (2b)^2 = 4b^2 \][/tex]
Now substitute [tex]\( 4b^2 \)[/tex] and [tex]\( 5b + 3 \)[/tex] back into the volume formula:
[tex]\[ V = \pi (4b^2) (5b + 3) \][/tex]

5. Distribute [tex]\( 4b^2 \)[/tex] inside the parentheses:
Apply the distributive property:
[tex]\[ V = \pi \cdot 4b^2 \cdot (5b + 3) = \pi \cdot (4b^2 \cdot 5b + 4b^2 \cdot 3) \][/tex]

6. Simplify further:
Calculate each term inside the parentheses:
[tex]\[ 4b^2 \cdot 5b = 20b^3 \][/tex]
[tex]\[ 4b^2 \cdot 3 = 12b^2 \][/tex]
Therefore:
[tex]\[ V = \pi (20b^3 + 12b^2) \][/tex]

7. Combine the terms to get the final expression:
[tex]\[ V = 20\pi b^3 + 12\pi b^2 \][/tex]

Thus, the volume of the cylinder in terms of [tex]\( b \)[/tex] is:
[tex]\[ V = 20\pi b^3 + 12\pi b^2 \][/tex]