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Mathematics

Non-Euclidean Geometry and the Curvature of Space

Quick fact

On a sphere, a triangle's angles can sum to more than 180 degrees – for example, a triangle with vertices at the North Pole and two points on the equator can have three 90-degree angles, summing to 270 degrees.

Why this is interesting

You probably learned that the angles of a triangle always add up to 180 degrees – but what if you draw a triangle on an orange? Or on a saddle?