A) 12
B) 13
C) 15
D) 17
Correct Answer: B
Solution :
Let the radius of the base of the cone be 5x cm and its h be12x cm. \[\therefore \] \[V=\frac{1}{3}\pi {{r}^{2}}h\] \[\Rightarrow \] \[314\frac{2}{7}=\frac{1}{3}\times \frac{22}{7}\times 5x\times 5x\times 12x\] \[\Rightarrow \] \[{{x}^{3}}=\frac{2200\times 3\times 7}{7\times 22\times 25\times 12}=1\] \[\Rightarrow \] \[x=1\] \[\therefore \] Slant height of the cone \[=\sqrt{{{5}^{2}}+{{12}^{2}}}=\sqrt{25+144}\] \[=\sqrt{169}=13\,cm\] Note for a right circular cone, \[{{5}^{2}}+{{12}^{2}}={{13}^{2}}\]You need to login to perform this action.
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