Banking Quantitative Aptitude Sample Paper Quantitative Aptitude Sample Paper-46

What is the appropriate total surface area of a right circular cone of height 14 cm and base radius 7 cm?                                                                                                                        [IBPS (PO/MT) 2015]

A) 510

B) 511

C) 490

D) 505

E) 499

Correct Answer: E

Solution :

Height of cone, \[h=14\,\,cm,\]Radius of cone, \[r=7\,\,cm\]

\[\therefore \]Slant height, \[l=\sqrt{{{h}^{2}}+{{r}^{2}}}=\sqrt{{{14}^{2}}+{{7}^{2}}}\]

\[=\sqrt{196+49}=\sqrt{245}=15.65\]

So, total surface area of cone \[=\pi r\,\,(l+r)\]

\[=\frac{22}{7}\times 7(15.65+7)\approx 499\]