Question

The radius of the base and the height of a right circular cone are $7$ cm and $24$ cm respectively Find the total surface area of the cone

• A. $70.4$ cm${}^2$
• B. $704$ cm${}^2$
• C. $7.04$ cm${}^2$
• D. $0.704$ cm${}^2$

Answer 1

Answer: (B)

The correct option is A $704$ cm${}^2$
Given : radius $\left(r\right)=7$ cm height (h)$=2$ cm Then
$l^2=h^2+r^2={24}^2+7^2$
or l=$\sqrt{625}$ cm = 25 cm
Total surface area of the cone = Curved surface area + Area of base
$=\pi rl+\pi r^2=(\frac{22}{7}\times 7\times 25)+(\frac{22}{7}\times 7\times 7)=704c{m}^2$