How to solve this Math problem?

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1

<p><a href="http://img404.imageshack.us/img404/8451/fv7h.png%5B/url%5D"&gt;http://img404.imageshack.us/img404/8451/fv7h.png&lt;/a&gt;&lt;/p>

2

<p>Let E be the intersection of AC, BD. Then BD:AC = BE:AE = sqrt(3):1.</p>