CBSE BOARD XII, asked by anshu6382, 7 months ago

From a solid cylinder of height 12 centimetre and diameter 10 cm a conical cavity of same height and same diameter is hollowed out find the total surface area of remaining solid​

Answers

Answered by shomekeyaroy79
6

GIVEN:-

•Radius of the cylinder=5cm

•Height of the cylinder =12 cm

TO FIND OUT:--

• The volume and the surface area of the remaining solid

SOLUTION :-

\begin{gathered}\textsf{formula used}\begin{cases} \bf volume \: _{cylinder} = \pi r {}^{2} h\\ \bf CSA_{cylinder} = 2 \pi rh\\ \bf CSA\: _{cone}= \pi rl\\ \bf \: volume \: _{cone} = \frac{1}{3} \pi r {}^{2} h \end{cases}\end{gathered} </p><p>formula used </p><p>⎩</p><p>⎪</p><p>⎪</p><p>⎪</p><p>⎪</p><p>⎨</p><p>⎪</p><p>⎪</p><p>⎪</p><p>⎪</p><p>⎧</p><p>

Now ,</p><p> \\ </p><p>\begin{gathered}\bf volume \: _{cylinder} \: = {\bigg (} \frac{22}{7} \times 5 \times 5 \times 12{ \bigg)cm {}^{3} } \\ \\ \: \: \: \: \: \: \: \: \: \: \: \: \: = \bf \frac{6600}{7} cm {}^{3}\end{gathered}volumecylinder=(722×5×5×12)cm3=76600cm3</p><p></p><p></p><p>

volume \: cone=(31×722×5×5×12) \: cm3 \\ =72200cm3</p><p></p><p></p><p>

•Volume of the remaining solid =(volume of the cylinder) -(volume of the cone)

\begin{gathered}\bf \implies { \bigg(} \frac{6600}{7} - \frac{2200}{7}{ \bigg)} cm {}^{3} = \frac{4400}{7} cm {}^{3} = 628.57 \: cm {}^{3} \\ \\\end{gathered} </p><p>⟹( </p><p>7</p><p>6600</p><p>	</p><p> − </p><p>7</p><p>2200</p><p>	</p><p> )cm </p><p>3</p><p> = </p><p>7</p><p>4400</p><p>	</p><p> cm </p><p>3</p><p> =628.57cm </p><p>3</p><p> </p><p>

Slant height of the cone(l)

\begin{gathered}\bf \: l = \sqrt{r {}^{2} + h {}^{2} } \\\end{gathered} </p><p>l= </p><p>r </p><p>2</p><p> +h </p><p>2</p><p> </p><p>	</p><p> </p><p>	</p><p> </p><p></p><p>\begin{gathered}\bf \implies l = \sqrt{5 {}^{2} + (12) {}^{2} } = \sqrt{169} = 13cm \\ \\\end{gathered} </p><p>⟹l= </p><p>5 </p><p>2</p><p> +(12) </p><p>2</p><p> </p><p>	</p><p> = </p><p>169</p><p>	</p><p> =13cm</p><p>	</p><p> </p><p></p><p>\begin{gathered}\textsf{CSA} \bf_{cone}={\bigg (} \frac{22}{7} \times 5 \times 13 { \bigg)}cm² = \frac{1430}{7} cm² \\\end{gathered} </p><p>CSA </p><p>cone</p><p>	</p><p> =( </p><p>7</p><p>22</p><p>	</p><p> ×5×13)cm²= </p><p>7</p><p>1430</p><p>	</p><p> cm²</p><p>	</p><p> </p><p></p><p>\begin{gathered}\textsf{CSA} \bf_{cylinder}= {\bigg (} 2 \times \frac{22}{7} \times 5 \times 12{ \bigg)}= \frac{2640}{7} cm² \\ \\\end{gathered} </p><p>CSA </p><p>cylinder</p><p>	</p><p> =(2× </p><p>7</p><p>22</p><p>	</p><p> ×5×12)= </p><p>7</p><p>2640</p><p>	</p><p> cm²</p><p>	</p><p> </p><p></p><p></p><p> </p><p></p><p></p><p>

Now, area of upper circular base of base of cylinder =

\begin{gathered}= \bf \pi r {}^{2} sq. \: unit \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = \bf{ \bigg(} \frac{22}{7} \times 5 \times 5 { \bigg)}cm {}^{2} = \frac{550}{7} cm {}^{2}\end{gathered} </p><p>=πr </p><p>2</p><p> sq.unit</p><p> =( </p><p>7</p><p>22</p><p>	</p><p> ×5×5)cm </p><p>2</p><p> = </p><p>7</p><p>550</p><p>	</p><p> cm </p><p>2

•Whole surface area of the remaining solid =CSA(cylinder)+CSA(cone)+area of upper base of cylinder

\begin{gathered}\implies\bf { \bigg(} \frac{2640}{7} + \frac{1430}{7} + \frac{550}{7} { \bigg)}cm {}^{2} = 660cm {}^{2} \\\end{gathered} </p><p>⟹( </p><p>7</p><p>2640</p><p>	</p><p> + </p><p>7</p><p>1430</p><p>	</p><p> + </p><p>7</p><p>550</p><p>	</p><p> )cm </p><p>2</p><p> =660cm </p><p>2</p><p> </p><p>

Answered by Anonymous
15

GIVEN:-

•Radius of the cylinder=5cm

•Height of the cylinder =12 cm

TO FIND OUT:--

• The volume and the surface area of the remaining solid

SOLUTION :-

 \textsf{formula used}\begin{cases} \bf volume   \: _{cylinder} =  \pi  r {}^{2} h\\ \bf  CSA_{cylinder}  = 2 \pi rh\\ \bf CSA\: _{cone}=  \pi  rl\\ \bf \: volume   \: _{cone} =  \frac{1}{3}  \pi r {}^{2} h</p><p></p><p></p><p>\end{cases}

Now ,

 \bf volume   \: _{cylinder}  \:  =   {\bigg (} \frac{22}{7} \times 5 \times 5 \times 12{ \bigg)cm {}^{3} }  \\ \\   \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \: =   \bf \frac{6600}{7}  cm {}^{3}

 \bf  \: volume \: _{cone}  \: ={  \bigg(} \frac{1}{3} \times  \frac{22}{7} \times 5 \times 5  \times 12 { \bigg)}cm {}^{3}    \\  \\ \:  \:  \:  \:  \:  \:  \:  \:   =  \bf \frac{2200}{7} cm {}^{3}

•Volume of the remaining solid =(volume of the cylinder) -(volume of the cone)

 \bf \implies { \bigg(} \frac{6600}{7}  -  \frac{2200}{7}{  \bigg)} cm {}^{3}  =  \frac{4400}{7} cm {}^{3}  = 628.57 \: cm {}^{3}  \\  \\

•Slant height of the cone(l)

 \bf \: l =  \sqrt{r {}^{2} + h {}^{2}  }  \\

 \bf  \implies l =  \sqrt{5 {}^{2} + (12) {}^{2}   }   =   \sqrt{169} = 13cm \\   \\

 \textsf{CSA} \bf_{cone}={\bigg (} \frac{22}{7}  \times 5 \times 13 { \bigg)}cm² =  \frac{1430}{7} cm² \\

 \textsf{CSA} \bf_{cylinder}= {\bigg (} 2 \times \frac{22}{7}  \times 5 \times 12{ \bigg)}= \frac{2640}{7} cm² \\  \\

•Now, area of upper circular base of base of cylinder =

  = \bf  \pi r {}^{2}  sq. \: unit \\  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \ \:  \:  \:   \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  =  \bf{ \bigg(} \frac{22}{7}  \times 5 \times 5 { \bigg)}cm {}^{2}  =  \frac{550}{7} cm {}^{2}

•Whole surface area of the remaining solid =CSA(cylinder)+CSA(cone)+area of upper base of cylinder

  \implies\bf { \bigg(} \frac{2640}{7}  +  \frac{1430}{7}  +  \frac{550}{7}  {  \bigg)}cm {}^{2} = 660cm {}^{2}   \\

Similar questions