Using Nets to Find the Surface Area of Prisms

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Objective

SWBAT describe and find the surface area of prisms using a net

Big Idea

Students develop an intuitive understanding of how surface area formulas are derived.

Lesson Beginning

5 minutes

I will hold up a cardboard box and ask: "How would you describe the surfaces of this box?"  I will accept a variety of answers, but guide the answers toward the faces of the box.  Then I'll ask:  "What do you think the math term surface area means?"  Again, I will take a variety of answers, but I will lead the answers toward a definition of surface area.  At the very least, I want students to realize that the term itself "surface area" describes the meaning; find the area of the surfaces.  Based on this, I will ask the students how we would find the surface area of the box.   I may need to again guide the students with questions like: What shapes are the surfaces?  How do we find the area of each face?  What should we do with the areas of each face? After this I will pose the essential question of the lesson:  how can you use a net to find the surface area of a prism? I will show the exit ticket at this point.  We will then briefly discuss these problems in context to the questions above.  The discussion here should be very general and very brief.

40 minutes

Lesson End

10 minutes

We will summarize the lesson's findings by asking, How can a net help you to find the surface area of a solid?  We’ll discuss this for 1-2 minutes.  Students will then be given an exit ticket