Ten stones, of identical shape and size, are used to make an arch, as shown in the diagram. Each stone has a cross-section in the shape of a trapezium with three equal sides. What is the size of the smallest angles of the trapezium?
Select one option, then click Submit.
13
15
16
17
18
Select an option, then submit.
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Intermediate Mathematical Challenge 2005 (2005)
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