Question

If the radius and slant height of a cone are in the ratio 7 ratio 13 and its curved surface area is 286 cm square find its radius

Answer 1

Curved surface area of cone = 286 cm^2

r : l = 7 : 13

CSA of cone = πrl

πrl = 286

22/7×r×l = 286

rl = 91 cm ---------> 1

Now according to question..

r/l = 7/13

13r = 7l

13r/7 = l --------> 2

Now put the value of l from eq 2 to eq 1

r × 13r/7 = 91

13r^2 = 637

r = 7

So the base radius of the cylinder is 7 cm.

Answer 2

Answer:

Let r/1 = 7/13x

Curved surface area CSA=286 cm2

But CSA=πrl

∴286 = 22/7 × 7x × 13x

or x2 = 286/22×13 = 1

or x = 1

∴ r=7 cm

∴ Diameter d=14 cm

Step-by-step explanation: