# Undoing a pentagon

Geometry Level 3

A white rectangular paper $$ABCD$$ with an area of $$20\text{ cm}^2$$ is bent as shown, forming a pentagon $$BCD'EF$$ with an area of $$14 \text{ cm}^2$$. If we paint both sides of this pentagon in blue and undo the fold, the rectangle will have an unpainted area. What is the area of this region?

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