Question

Anita is hosting a birthday party for her friends. She decided to make some conical party hats for her ten friends. The party hats are of height 24 cm with a radius of 7 cm made out of party paper. What is the total cost of the party paper if it costs $₹0.035perc{m}^2$?

• A. 262.39 m²
• B. 463.39 m²
• C. 662.39 m²
• D. 563 m²

Answer 1

The correct option is B

463.39 m²

Given, $r=7cm,h=24cm$

slant height, $l^2=h^2+r^2={24}^2+7^2=625\Rightarrow l=25cm$

Curved surface area of cone $=\pi rl=\pi \times 7\times 25c{m}^2$

Total cost of party paper $=10\times 0.035\times \frac{22}{7}\times 7\times 25=₹192.5$