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Bound to Be

Age 14 to 16 Challenge Level:

Bounded area $ABCD$ is a square of side 1 unit. Arc of circles with centres at $A, B, C, D$ are drawn in.

Prove that the area of the central region bounded by the four arcs is:

$(1 + \pi/3 + \sqrt{3})$ square units.

The NRICH Project aims to enrich the mathematical experiences of all learners. To support this aim, members of the NRICH team work in a wide range of capacities, including providing professional development for teachers wishing to embed rich mathematical tasks into everyday classroom practice.
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