We know that one regular hexagon is consist of the six equilateral triangles.
One of this is ΔAFM every angle in this triangle worth 60°, according to this
∡AFM=60°.
ΔABC is isosceles triangle with angle ∡ABC=120°, because every interior angle in regular hexagon worth 120°.
Angles ∡BAC=∡BCA=30°. Total sum of angles in one triangle is 180°.
∡ACF≅∡BCA=30° at the end we can conclud that angle ∡FAC=90° WHY?
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