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Mystery #2Tier 1shapes and structures

Why are cranes, bridges and towers packed full of triangle shapes?

Look closely at a crane, a railway bridge or an electricity pylon and you will spot the same shape over and over again: the triangle. Builders could use squares or rectangles, but they choose triangles time after time. Why are cranes, bridges and towers packed full of triangle shapes?

The Forth Bridge in Scotland, its huge red steelwork made up of triangle after triangle, with a train crossing high above the water
Photo: Kabelleger / David Gubler · CC BY-SA 4.0 · via Wikimedia Commons

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Why do you think a triangle holds firm when a square might not?

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