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Source: Chalkdust issue 07

In the diagram below, \(ABDC\) is a square. Angles \(ACE\) and \(BDE\) are both 75°.

Is triangle \(ABE\) equilateral? Why/why not?

If you enjoyed this puzzle, check out Sunday Afternoon Maths LXIII,

puzzles about triangles, or a random puzzle.

puzzles about triangles, or a random puzzle.