Answer:
[tex]4116\; {\rm ft^{3}}[/tex], assuming that the two cylinders are of the same height.
Step-by-step explanation:
The volume of a cylinder of radius [tex]r[/tex] and height [tex]h[/tex] is [tex]\pi\, r^{2}\, h[/tex].
If the two cylinders are of the same height [tex]h[/tex], the volume of the two cylinders would be proportional to the square of their radii.
Let [tex]r_{0}[/tex] and [tex]V_{0}[/tex] denote the radius and volume of the smaller cylinder. Similarly, let [tex]r_{1}[/tex] and [tex]V_{1}[/tex] denote the radius and volume of the larger cylinder. Assuming that the height of both cylinders is [tex]h[/tex]:
[tex]V_{1} = \pi\, {r_{1}}^{2}\, h[/tex].
[tex]V_{0} = \pi\, {r_{0}}^{2}\, h[/tex].
Hence, [tex](V_{1}) / (V_{0})[/tex] (ratio between the volume of the larger cylinder and the volume of the smaller cylinder) would be:
[tex]\begin{aligned}\frac{V_{1}}{V_{0}} &= \frac{\pi\, {r_{1}}^{2}\, h}{\pi\, {r_{0}}^{2}\, h} =\frac{{r_{1}}^{2}}{{r_{0}}^{2}}\end{aligned}[/tex].
In this question, it is given that:
- the volume of the smaller cylinder is [tex]V_{0} = 756\; {\rm ft^{3}}[/tex].
- the radius of the smaller cylinder is [tex]r_{0} = 3\; {\rm ft}[/tex].
- the radius of the larger cylinder is [tex]r_{1} = 7\; {\rm ft}[/tex].
Rearrange the equation [tex]\begin{aligned}\frac{V_{1}}{V_{0}} &= \frac{{r_{1}}^{2}}{{r_{0}}^{2}}\end{aligned}[/tex] to find an expression for [tex]V_{1}[/tex], volume of the larger cylinder:
[tex]\begin{aligned}V_{1} &= \frac{{r_{1}}^{2}\, V_{0} }{{r_{0}}^{2}} \\ &= \frac{{(7\; {\rm ft})}^{2}}{{(3\; {\rm ft})}^{2}} \times (756\; {\rm ft^{3}}) \\ &= 4116\; {\rm ft^{3}} \end{aligned}[/tex].
