The radius and slant height of a cone are in the ratio of 4 : 7. If it

1.	The radius and slant height of a cone are in the ratio of 4 : 7. If its curved surface area is 792 cm2, find its radius. (Use π = 22/7)
Answer» We have, Let radius of cone = r =4x, Let slant height = l =7x Area of curved surface = πrl = 792 cm² Now, πrl = 792 = \(\frac{22}{7}\) \(\times\)4x \(\times\) 7x = 792 = x² =9 = x = 3 cm ∴r = 4 × 3 = 12 cm l = 7×3 = 21 cm

The radius and slant height of a cone are in the ratio of 4 : 7. If its curved surface area is 792 cm2, find its radius. (Use π = 22/7)

Answer»

We have,

Let radius of cone = r =4x,

Let slant height = l =7x

Area of curved surface = πrl

= 792 cm²

Now,

πrl = 792

= \(\frac{22}{7}\) \(\times\)4x \(\times\) 7x

= 792

= x² =9

= x = 3 cm

∴r = 4 × 3 = 12 cm

l = 7×3 = 21 cm