question_answer

The frustum of a right circular cone has the diameters of base 10 cm, of top 6 cm and a height of 5 cm. Find its slant height.

A) \[\sqrt{29}\,cm\]

B) \[3\sqrt{3}\,cm\]

C) \[\sqrt{13}\,cm\]

D) \[\sqrt{13}\,cm\]

Correct Answer: A

Solution :

[a] Slant height \[=\sqrt{{{h}^{2}}+{{(R-r)}^{2}}}\] \[=\sqrt{25+{{(5-3)}^{2}}}=\sqrt{29}\,cm\]