Question

Raghu wants to make a closed aluminium cone for his science project. The slant height and radius of the cone should be 10 cm and 7 cm respectively. The area of the aluminium sheet required to make the cone is_____.
$(Use\pi =\frac{22}{7})$

• A. $400{cm}^2$
• B. $267{cm}^2$
• C. $258{cm}^2$
• D. $374{cm}^2$

Answer 1

The correct option is D

$374{cm}^2$

Given,
Radius $\left(r\right)$ = 7 $\text{cm}$
Slant height $\left(l\right)$ = 10 $\text{cm}$

Area of the aluminium sheet required
=Total surface area of the cone
= $\pi r(l+r)$
= $\frac{22}{7}\times 7(10+7)$
= 374 ${\text{cm}}^2$

Hence, the area of the aluminium sheet required is 374 ${\text{cm}}^2.$