Question

Total surface area of cone is 616 sq cm. If the slant height of the
cone is three times the radius of its base then complete the
following activity to find the radius of a cone.​

Answer 1

Step-by-step explanation:

TSA of a cone= πr²+πrl= πr(r+l)

let r be the radius,

l= 3r

616cm²= πr(r+l)

616cm²= 22/7 ×r(r+3r)

56cm²×7= 2r×4r

56cm²×7= 8r²

r²= 56cm²×7/8

r=√7cm²×7

= 7cm

Therefore, slant height (l)= 3r= 3×7cm= 21cm