Question

the sphere,a cylinder,and a cone have same radius and same height find the ratio of curved surface area ​

Answer 1

Step-by-step explanation:

Since, the height of a sphere is the diameter, the cone and cylinder have height 2r. 

Then 

Curved surface area of Sphere=4πr²

Curved surface area of cylinder =2πr(2r)=4πr²

Curved surface area of cone = πrl

where, l=(r2+h2)=(r2+(2r)2)=5r2=r5

⇒ Curved surface area of cone =π5r2

Now, 

ratio of CSA 's a sphere ,cylinder and a cone = 4πr2:2πrh:πrl

=4πr2:4πr2:πr25

=4:4:5

Answer 2

Answer:

4:4:5

Step-by-step explanation:

Curved surface area of Sphere=4πr²

Curved surface area of cylinder =2πr(2r)=4πr²

Curved surface area of cone = πrl

where, l=(r2+h2)=(r2+(2r)2)=5r2=r5

⇒ Curved surface area of cone =π5r2

Now,  

ratio of CSA 's a sphere ,cylinder and a cone = 4πr2:2πrh:πrl

=4πr2:4πr2:πr25

=4:4:5