Question

A right cone has a radius of 13 cm and an altitude of 52 cm. Find its surface area.



A. 2,668.7 cm2
B. 865.8 cm2
C. 849.5 cm2
D. 2,720.0 cm2

Answer 1

Answer:

Option B. $865.8\pi\ cm^{2}$

Step-by-step explanation:

we know that

The surface area of the cone is equal to

$SA=\pi r^{2} +\pi rl$

we have

$r=13\ cm$

$h=52\ cm$

Find the slant height l

Applying Pythagoras \theorem

$l^{2}=r^{2} +h^{2}$

substitute the values

$l^{2}=13^{2} +52^{2}$

$l^{2}=2,873$

$l=53.6\ cm$

Find the surface area

$SA=\pi(13)^{2} +\pi(13)(53.6)=865.8\pi\ cm^{2}$