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UKMT Junior Kangaroo, 2016

Geometry Difficulty 2.0 Junior Find the answer United Kingdom

Four circles of radius 5 cm touch the sides of a square and each other, as shown in the diagram. On each side of the square, an equilateral triangle is drawn to form a four-pointed star. What is the perimeter of the star?

(A) $40$ cm (B) $80$ cm (C) $120$ cm (D) $160$ cm (E) $200$ cm

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