Building Pyramids

Today in grade 9 we were looking at the volume of pyramids and cones, compared to their prisms of the same height.

We used water to see that a pyramid can be filled and poured 3 times into a prism, just like the video shows.

We then had the challenge of building square based pyramids with a volume of 300 cubic centimetres.

We know that the volume of the prism with same length, width and height as the pyramid would be 900 cubic centimetres.

We noticed that many groups made pyramids that were shorter than they had planned.

Many groups had not considered that the slant height is different from the pyramid height, and we need to use the pythagorean theorem.

There was a good amount of productive struggle in each group as we needed to readjust our triangles a few times to achieve the correct height for the pyramids.