Gr 7 · 45 min
Volume of prisms
Coming soon. We're checking this lesson against the app, step by step, so it works when you run it with a class. You can read the plan now. The lesson pack, teaching mode and assigning open once it's checked.
Base area × length works for every prism: triangles, pentagons, hexagons.
Ontario Gr 7 · Spatial Sense E2 · Common Core 7.G.B.6
Learning goals
- Find the volume of a prism as base area × length
- Find the surface area of prisms with different bases
Plan
- 1
Slice it10 minYou lead
A prism is the same shape all the way through. Its volume is the area of the end times the length.
- 2
Hexagon area15 minStudents
Split the hexagon into 6 triangles from the centre. Each is ½ × side × apothem; the apothem is the dotted line from the middle of the hexagon to a side.
- 3
Volume and area15 minStudents
Find the volume and the surface area. Check against FoldNets' readout.
- 4
Compare5 minStudents
Open the pentagonal and triangular prisms with the same side and length (both open from this lesson's page). Which holds the most?
To talk about
- Why does base × length work for a prism but not a pyramid?
- A prism's volume doubled. What might have changed?