Mary Koerber Geometry in two dimensional and three dimensional ...

Opening ActivityIntroduce a pyramid to students. Ask students how they think you can find the surfaceareas of this pyramid.Expected response: find the areas of the different parts and add them up.Discuss the difference between bases that are of a regular shape and bases that are not.Ask students which kind of shapes would be quicker to find out the surface area and askthem why.Expected response:A regular shape with a regular base . This way the area of one lateral side is needed sincethey will all be the same.Introduce how to calculate surface area and go into the developmental activity.Developmental Activity (Surface Areas)PyramidsHave students make their own regular pyramids out of pipe cleaners.Have students measure the slant height and the length of an edge of a base.The surface area of a regular pyramid is the sum of the lateral area and the area of thebase.s = side. l = slanted s - *lheightThe area of each lateral face is2 .Multiply this area by the number of sides on your base to get the lateral area.Find the area of the base and add it to the lateral area to get the surface area.After students have completed this activity, ask a few volunteers to discuss their pyramidthey made with the lengths and explain how they got the surface area.Koeber – Page 20