Surface Area

If dealing with 3D shapes you might be asked to find the surface area of a shape. One way may be to look at its net.

Nets

A net is just a 3D shape folded flat. E.g. here is the net of a square.cube netIn a questions you can find the surface area just by adding up all the areas of the shapes that make the net.

Surface Area Of A Sphere

Surface area of a sphere = 4πr2sphere volume

 

Surface Area Of A Cone

Surface area of a cone = πrl + πr2

Note: l is the slanted height.cone volumeSurface Area Of A Cylinder

Surface area of a cylinder = 2πrh + 2πr2prism volume