Question

find the tsa of cone ,if its slant height is 21 cm and radius is 7cm​

Answer 1

Answer :

616cm²

Explanation :

A cone with slant height 21cm and radius of the base 7cm.

Find it's T. S. A. (Total surface area).

Formula :

$\rm \longrightarrow Total \: surface \: area \: of \: cone = \pi r(l + r)$

Where,

• Taking $\pi = \dfrac{22}{7}$
• l(slant height) = 21cm.
• r(radius) = 7cm.

On substituting the given values :

$\sf \longrightarrow \: \dfrac{22}{7} \times 7(21 + 7)$

$\sf \longrightarrow \: 22(21 + 7)$

$\sf \longrightarrow \: 22(28)$

$\sf \longrightarrow \: 616 {cm}^{2}$

${ \underline{ \sf{ \therefore{T. S. A. \: of \: the \: cone = {616cm}^{2} }}}}$

Answer 2

Answer:

$\begin{gathered}{\Large{\textsf{\textbf{\underline{\underline{\color{green}{Given:}}}}}}}\end{gathered}$

• ⇢ Slant height of cone = 21 cm
• ⇢ Radius of cone = 7 cm

$\begin{gathered}\end{gathered}$

$\begin{gathered}{\Large{\textsf{\textbf{\underline{\underline{\color{green}{To Find:}}}}}}}\end{gathered}$

• ⇢ TSA of cone

$\begin{gathered}\end{gathered}$

$\begin{gathered}{\Large{\textsf{\textbf{\underline{\underline{\color{green}{Using Formula:}}}}}}}\end{gathered}$

$\dag{\underline{\boxed{\sf{Total \: surface \: area \: of \: Cone ={{\pi}r(l+r)}}}}}$

$\begin{gathered}\end{gathered}$

$\begin{gathered}{\Large{\textsf{\textbf{\underline{\underline{\color{green}{Solution:}}}}}}}\end{gathered}$

$\quad{: \implies{\sf{Total \: surface \: area \: of \: Cone ={{\pi}r(l+r)}}}}$

• ⇢ Substituting the values

$\quad{: \implies{\sf{Total \: surface \: area \: of \: Cone ={{\dfrac{22}{7} } \times 7(21+7)}}}}$

$\quad{: \implies{\sf{Total \: surface \: area \: of \: Cone ={{\dfrac{22}{\cancel{7}}} \times{\cancel{7}}(21+7)}}}}$

$\quad{: \implies{\sf{Total \: surface \: area \: of \: Cone ={22 \times{(28)}}}}}$

$\quad{: \implies{\sf{Total \: surface \: area \: of \: Cone ={22 \times 28}}}}$

$\quad{: \implies{\sf{Total \: surface \: area \: of \: Cone ={616 \: {cm}^{2} }}}}$

$\begin{gathered} \dag{\overline{\underline{\boxed{\bf{\color{red}{TSA = 616 {cm}^{2}}}}}}}\end{gathered}$

• ⇢ Henceforth,The TSA of cone is 616 cm².

$\begin{gathered}\end{gathered}$

$\begin{gathered}{\Large{\textsf{\textbf{\underline{\underline{\color{green}{Diagram:}}}}}}}\end{gathered}$

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• ⇢ Request: Please see the answer from website Brainly.in.
• ⇢ Please check given attachment also!

$\begin{gathered}\end{gathered}$

$\begin{gathered}{\Large{\textsf{\textbf{\underline{\underline{\color{green}{Learn More:}}}}}}}\end{gathered}$

$\begin{gathered}{\textsf{\textbf{\underline{\underline{\color{red}{Cone:}}}}}}\end{gathered}$

• ⇢ A cone is a three-dimensional solid geometric figure having a circle at one end and a pointed edge at the other.  
• ⇢ A cone can be carved out from a cylinder.
• The three elements of the cone are its radius, height, and slant height.
• ⇢ Radius (r) of a cone is the same as the radius of the circle at the end of the cone.  
• ⇢ Height (h) is the distance from the center of the circle at one end to the pointed edge at the other end.
• ⇢ Slant Height (s) is the distance along the curved surface, drawn from the edge at the top to the circumference of the circle at the base.

$\begin{gathered}{\textsf{\textbf{\underline{\underline{\color{red}{Formulas of Cone:}}}}}}\end{gathered}$

The relation between slant height, height and rdius of a cone in math.

$\dashrightarrow \sf{ s = \sqrt{( {r}^{2} + {h}^{2} )}}$

Volume of Cone

$\dashrightarrow{\sf{Volume \: of \: a \: Cone = \dfrac{1}{3}{\pi}{r}^{2}h}}$

Curved Surface Area

$\dashrightarrow{\sf{curved \: surface \: area \: of \: cone= {{\pi}rl}}}$