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Solid: A composite solid made by subtracting a cone from a cylinder. The radius of the cylinder is 3 units and the height is 4 units.
Surface Area: 48Ď€ square units
We will start by analyzing the given triangle.
We see that the revolved triangle creates a composite solid made by subtracting a cone from a cylinder. The radius of the cylinder is 3 units and the height is 4 units. We are asked to find the surface area of the revolved solid. First, let's find the slant height of the cone, l.
r= 3, h= 4
Calculate power
Add terms
Rearrange equation
sqrt(LHS)=sqrt(RHS)
Calculate root
Let's find them!
Radius | r= 3 |
---|---|
Height | h= 4 |
Slant Height | l= 5 |
\text{L.A.}_\text{cone} | π r l=π ( 3)( 5)=15π |
\text{L.A.}_\text{col} | 2Ď€ r h=2Ď€ ( 3)( 4)=24Ď€ |
B | π r^2=π ( 3)^2=9π |
Finally, we will find the surface area of the composite solid, S.A.. \begin{gathered} \textcolor{darkviolet}{\text{S.A.}}=\text{L.A.}_\text{cone}+\text{L.A.}_\text{col}+B \\ \Downarrow \\ \textcolor{darkviolet}{\text{S.A.}}=\textcolor{darkorange}{15\pi}+\textcolor{darkorange}{24\pi}+\textcolor{darkorange}{9\pi}=\textcolor{darkviolet}{48\pi} \end{gathered} The surface area of the revolved solid is 48Ď€ square units.