Wednesday, April 16, 2008

Kevin T's Scribe

Todays class is about the surface area of a cylinder.

The Net of a cylinder

the cylinder has 3 shapes, 2 circles and a rectangle. To get the surface area of a cylinder follows this formula:

SA = (Pi x r²) + (2 x Pi x r) + ( Pi x r²)

In class we had a an example question: the height is 10 and the radius is 5. The circumference is the length of the rectangle so you get the area of the 3 shapes and add them together to ge the Surface area.

SA = (3.14 x 25) + (2 x 3.14 x 5) + ( 3.14 x 25)
= 78.5 + 314 + 78.5
= 417