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UKMT Junior Mathematical Challenge, 2017

Geometry Difficulty 2.0 Junior Find the answer United Kingdom

Seven squares are drawn on the sides of a heptagon so that they are outside the heptagon, as shown in the diagram. What is the sum of the seven marked angles?

(A) $315^\circ$ (B) $360^\circ$ (C) $420^\circ$ (D) $450^\circ$ (E) $630^\circ$

Figure for this problem

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