Today’s task was to make a pyramid with a volume of 300 cubic centimetres.  What was interesting was each group independently decided to use dimensions of the base as 10cmby 10cm and the height 9cm.

One group realized at first that the height of the triangles on the side needed to be longer than 9 in order to have the pyramid height be 9.  After a bit of reasoning, they divided the base in half, and used that along with the 9cm height and used the Pythagorean theorem to calculate the hypotenuse, which is the slant height, and the height of each triangle. Other groups decided that the 9cm should be the height of each triangle, which ended up with a slant height of 9cm. This makes a pyramid that is too short! Another group measured 9cm along the edge of the pyramid. This pyramid was even shorter than the other!

Some groups needed a few iterations before their pyramids were the right height.  Persistence pays off thought!  We persevered through several challenges today!

We calculated surface areas, and then set out to design a square based prism with a volume equal to our pyramid. We’ll build towers, and figure out the surface area of the combined solid.