Can you work out the dimensions of the three cubes?
This article outlines the underlying axioms of spherical geometry giving a simple proof that the sum of the angles of a triangle on the surface of a unit sphere is equal to pi plus the area of the triangle.
A spider is sitting in the middle of one of the smallest walls in a
room and a fly is resting beside the window. What is the shortest
distance the spider would have to crawl to catch the fly?
It is not necessary to use a lot of algebra for representation where students are not sufficiently confident with that.
A spreadsheet that allows volume to vary is powerful but only after students have established an understanding of the calculation process being carried out by the computer on their behalf.