Question

The curved surface area of a cone is 4070 cm² and its diameter is 70 cm. What is its slant height?

Answer 1

C.S.A. of a cone = πrl = 4070 cm² 

Diameter of the cone (d) = 70 cm 

Radius of the cone = r = d/2 = 70/2 = 35 cm 

Let its slant height be ‘l’. 

By problem, 

πrl = 4070 cm²

22/7 × 35 × l = 4070 

110 l = 4070 

l = \(\frac{4070}{110}\) = 37 cm 

∴ Its slant height = 37 cm.