The diagram shows a rectangle inside a regular decagon .
What is the ratio of the area of the rectangle to the area of the decagon?
Input note: give your ratio in its simplest form.
Select one option, then click Submit.
2 : 5
1 : 4
3 : 5
3 : 10
3 : 20
Select an option, then submit.
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Senior Mathematical Challenge 2018 (2018)
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