The diagram shows four equilateral triangles with sides of lengths 1, 2, 3 and 4. The area of the shaded region is equal to times the area of the unshaded triangle of side-length 1.
What is the value of ?
Select one option, then click Submit.
8
11
18
23
26
Select an option, then submit.
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Intermediate Mathematical Challenge 2017 (2017)
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