what is the surface area of a cone when the radius is 10 and so is the height.

Thanks DragonLance, i didn't know that :)

DarkBlaze

When you are making a post there is a dropdown insert menu up the ribbons.

One of those is 'special characters'  You will find lots of useful characters in there :)

Given the radius and height, the formula for the surface area of a cone is $${\mathtt{\pi}}$$r[r+(sqrt of h^2+r^2).

h for height, r for radius.

Plugging in the values: we get 10$${\mathtt{\pi}}$$[10+(sqrt200)]

Can you finish it from here?

S_area = ( pi * r) (r + √[r^2 + h^2] )     where r is the radius and h is the height  ..... so we have.....

S_area  = ( pi * 10 ) (10 + √[10^2 + 10^2] )  = (10*pi) *(10 + 10√2) = 758.48 sq units

How do you get the square root sign? I tried looking for it everywhere but never found it.

Hold down the ALT key and type 251

ALT 251 for √