Respuesta :

Solution,

Here,

S = Surface area of cone

r = Radius

l = length

Now,

S = πr^2 + πrl

or, S = πr(r + l)

or, S ÷ πr = r + l

or, S ÷ πr - r = l

or, l = S ÷ πr - r

Therefore,the formula for the length will be

l = S ÷ πr - r