Question

A solid cone of radius 4cm and vertical height 3cm has to be painted from outside except the base.Find the surface area to be painted.

Answer 1

since we need not paint the base area we calculate the lateral surface area (LSA)
LSA=π×r×l where r is the radius and l Is the slant height .
lateral height 'l'= √(r^2+h^2)
therefore l =√9+16
l =5
therefore
LSA= π×4×5
therefore the area to be painted = 62.831cm^2
hope you understood
Thank you

Answer 2

hii!!!

here's ur answer..

given :-

radius of the cone = 4cm

vertical height if the cone = 3cm

length^2 (slant height) = radius^2 + height^2

length^2 = 4^2 + 3^2

length^2 = 16 + 9

length^2 = 25

length = under root 25

length = 5cm

now, CSA (curved surface area) as we have to find the cost of painting the conical solid except base portion..

so CSA of the conical solid = pi*r*l

= 22/7 * 4 * 5

= 440/7cm^2

this much area will be painted.

hope this helps..!!