Question

the radius and slant height of a cone are in the ratio 4:7.If it's curved surface area is 792cm Sq. Find its radius

Answer 1

let the radius be 4x and l be 7x
CSA= πrl
=22/7*4x*7x=792
= 88x²=792
x=792/88=✓9=3
r=3*4=12cm

Answer 2

Let, the radius(r) be 4x and slant height(l) 7x...
Curved surface area = 792cm^2

According to the formula for curved surface area,

Curved surface area
$792= \pi \times r \times l \\ 792= 22 \div 7 \times 4x \times 7x$
792= 616x^2/7
792=88x^2
x^2= 9
x= 3

Radius= 4x = 4*3= 12 cm