IM 7.7.17 Lesson: Building Prisms

Autor:GeoGebra Classroom Activities, IM 6 – 8 Math

Here are some nets for various prisms.

What would this net look like when folded?

Here are the same nets for various prisms. What do you notice about the nets?

The base of a triangular prism has one side that is 7 cm long, one side that is 5.5 cm long, and one angle that measures 45°. Draw as many different triangles as you can with these given measurements.

Select one of the triangles you have drawn. Measure and calculate to approximate its area. Explain or show your reasoning.

Here is an an incomplete net. Follow these instructions to complete the net and assemble the triangular prism:

Draw an identical copy of the triangle you selected in the previous activity along the top of the rectangle, with one vertex on point

. Draw another copy of your triangle, flipped upside down, along the bottom of the rectangle, with one vertex on point

Determine how long the rectangle needs to be to wrap all the way around your triangular bases.

If you assembled your triangular prism, answer these questions.

What is the volume of your prism? Explain your reasoning.

If you stood up your prism so it is sitting on its triangular base,

If you were to cut your prism in half horizontally, what shape would the cross section be?

What is the surface area of your prism? Explain your reasoning.

If you were to cut your prism in half vertically, what shape would the cross section be?

Draw the base of your new prism and label the lengths of the sides.

Compare your prism with your partner’s prism. What is the same? What is different?

Find a way you can put your prism and your partner’s prism together to make one new, larger prism. Describe your new prism.

As you answer these questions about your new prism, look for ways you can use your calculations from the previous activity to help you.

What is the area of its base? Explain or show your reasoning.

What is its height? Explain or show your reasoning.

What is its volume? Explain or show your reasoning.

What is its surface area? Explain or show your reasoning.

How many identical copies of your prism would it take you to put together a new larger prism in which every dimension was twice as long? Explain or show your reasoning.