Problems

The volume of a pyramid is \(\frac{1}{3}Bh\), where \(B\) is the area of the base and \(h\) is the perpendicular height. What’s the volume of a regular tetrahedron with side length \(1\)?

The Great Pyramid of Giza is the largest pyramid in Egypt. For the purposes of this problem, assume that it’s a perfect square-based pyramid, with perpendicular height \(140\)m and the square has side length \(230\)m.

What is its volume in cubic metres?

A regular octahedron is a solid with eight faces, all of which are equilateral triangles. It can be formed by placing together two square based pyramids at their bases.

What is the volume of an octahedron with side length \(1\)?

In the picture below, there are the \(12\) pentominoes. Is it possible to tile a \(6\times10\) rectangle with them?

Show how to tile a \(5\times12\) rectangle with the twelve pentominoes.

Show how to tile a \(4\times15\) rectangle with the twelve pentominoes.

Is it possible to tile a \(3\times20\) rectangle with the twelve pentominoes?

Show to how to cover the plane with this cube net:

Show how to tile the plane with this cube net:

Queen Hattius has two prisoners and gives them a puzzle. If they succeed, then she’ll let them free. She will randomly put a hat on each of their heads. The hats could be red or blue. They will simultaneously guess the colour of their own hat, and if at least one person is correct, then they win.

Each prisoner can only see the other prisoner’s hat - and not their own. The prisoners aren’t allowed to communicate once they’re wearing the hats, but they’re allowed to come up with a strategy before.

What should their strategy be?