Spheres, cylinders and cones
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problemBall Packing
If a ball is rolled into the corner of a room how far is its centre from the corner?
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problemPacking 3D Shapes
What 3D shapes occur in nature. How efficiently can you pack these shapes together?
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problem2D-3D
Two circles of equal size intersect and the centre of each circle is on the circumference of the other. What is the area of the intersection? Now imagine that the diagram represents two spheres of equal volume with the centre of each sphere on the surface of the other. What is the volume of intersection?
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problemPack Man
A look at different crystal lattice structures, and how they relate to structural properties
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articleThe Dodecahedron Explained
What is the shortest distance through the middle of a dodecahedron between the centres of two opposite faces? -
articleCurvature of Surfaces
How do we measure curvature? Find out about curvature on soccer and rugby balls and on surfaces of negative curvature like banana skins. -
articleVolume of a Pyramid and a Cone
These formulae are often quoted, but rarely proved. In this article, we derive the formulae for the volumes of a square-based pyramid and a cone, using relatively simple mathematical concepts.
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articleMouhefanggai
Imagine two identical cylindrical pipes meeting at right angles and think about the shape of the space which belongs to both pipes. Early Chinese mathematicians call this shape the mouhefanggai.
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articleWhen the Angles of a Triangle Don't Add Up to 180 Degrees
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.