### All in the Mind

Imagine you are suspending a cube from one vertex (corner) and allowing it to hang freely. Now imagine you are lowering it into water until it is exactly half submerged. What shape does the surface of the water make around the cube?

### Qqq..cubed

It is known that the area of the largest equilateral triangular section of a cube is 140sq cm. What is the side length of the cube? The distances between the centres of two adjacent faces of another cube is 8cms. What is the side length of this cube? Another cube has an edge length of 12cm. At each vertex a tetrahedron with three mutually perpendicular edges of length 4cm is sliced away. What is the surface area and volume of the remaining solid?

### Painting Cubes

Imagine you have six different colours of paint. You paint a cube using a different colour for each of the six faces. How many different cubes can be painted using the same set of six colours?

# Weekly Problem 19 - 2008

##### Stage: 3 and 4 Challenge Level:

In total there are $12\times12\times12$ or $12^3$ cubes with edge length $1$cm. Each cube has twelve edges, so the sum of the lengths of the edges on one cube is $12$cm. Therefore the total length of all the edges of all the centimeter cubes is $12^3\times12 = 12^4$cm

This problem is taken from the UKMT Mathematical Challenges.

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