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Quadrilaterals: Overview

In the figure below, what is the value of $$x$$? ![](data:image/svg+xml;base64,<?xml version="1.0" encoding="utf-8"?>
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)
Incorrect. [[snippet]]
Incorrect. [[snippet]]
Incorrect. [[snippet]]
Incorrect. [[snippet]]
Correct. [[snippet]] Angles $$CED$$ and $$AED$$ are supplementary angles, so >$$\angle AED = 180^\circ - 120^\circ = 60^\circ$$. Since the sum of all angles in a triangle is 180°, you get >$$\angle DAE = 180^\circ - 90^\circ - 60^\circ = 30^\circ$$. Finally, looking at $$\triangle ABC$$, you get >$$\angle BCE = 180^\circ - 90^\circ - 30^\circ = 60^\circ$$.
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