Question

Choose the correct alternative answer for the following question.

 Find the curved surface area of a cone of radius 7 cm and height 24 cm.

Options

• 440 cm² 

• 550 cm² 

• 330 cm² 

• 110 cm²                  

Answer 1

Radius of the cone, r = 7 cm 
Height of the cone, h = 24 cm
Let l be the slant height of the cone.

\[l = \sqrt{r^2 + h^2} = \sqrt{7^2 + {24}^2} = \sqrt{49 + 576} = \sqrt{625}\] = 25 cm

∴ Curved surface area of the cone = \[\pi r l = \frac{22}{7} \times 7 \times 25\] = 550 cm²