# Side Squared

Geometry Level 4

$$ABCD$$ is a quadrilateral where $$AB=AD=CD=l$$. $$\triangle BCD$$ is right, and $$\triangle ABD$$ is isosceles. It is given that $$BC=\color{#03D300}{X}=l^2$$. By considering $$\color{blue}{\alpha}$$, or otherwise, find the set of all possible values of $$\color{#03D300}{X}$$.

Input $$a+b$$ as your answer, where $$a<\color{#03D300}{X}<b$$.

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