Question

Find the total surface area of a cone, if its slant height is $21m$ and diameter of its base is $24m$.

• A. $1244.57m^2$
• B. $2244.57m^2$
• C. $1144.57m^2$
• D. $1277.57m^2$

Answer 1

The correct option is A $1244.57m^2$

Given: $l=21m,r=\frac{24}{2}=12m$
Total surface area of the cone $=\pi r(r+l)=\frac{22}{7}\times 12\times (21+12)$
$=1244.57m^2$