Question

5. The radius and slant height of a cone are in the ratio of 2:7. If its curved surface area is 704 cm², find its radius (r), slant height (l) and height (h).​

Answer 1

Answer: 12 cm

Step-by-step explanation:

The ratio of the radius and height of the cone is 2 : 7.

Let the radius of the cone be 2x and the height be 7x

So,  

Curved surface area of the cone = πrl

792 = 22/7*2x*7x  

x² = (792*7)/(22*2*7)

x² = 9

x = √9

x = 3 cm

So, the radius of the cone = 4 × 3 = 12 cm.