Google Classroom
GeoGebra Classroom

# Net + Surface Area of a Triangular Prism and Cylinder

For the Triangular Prism below, play with the sliders on the right. If you click "Start" it will auto open or close the shape, or you can slide it yourself.

## Triangular Prism Question:

Unfold the shape and click the "Show Perimeter of Base" button. The length of the red line will be important to finding the area of the rectangle. Fold the shape. What do we call the length of the red line (think about terms we'd use in relation to the triangle)?

Surface Area of a Right Cylinder: The surface area of an object is the number of square units needed to cover all of the surfaces of that object. Let's pull this cylinder apart to see what surfaces we need to cover! Pull the slider along the top from left to right to pull the surfaces of our cylinder apart. After you pull the surfaces completely apart, use the results to answer the questions below.

Question 1: What shapes are faces of our right cylinder?

Question 2: By unfolding this right cylinder, have we changed the amount of square units needed to cover these faces?

Select all that apply
• A
• B
Check my answer (3)

Question 3: How are the area of the "net" we end up with on the left and the surface area of our original cylinder related?

Question 4: How could we compute the length of the purple edge of our rectangle? (Hint: look at the "other" purple edge in the picture)

Question 5: Describe a plan for finding the surface area of our right cylinder (What shapes are you adding together?)