A vertically straight tree, $15$ $m$ high, is broken by the wind in such a way that its top just touches the ground and makes an angle of $60^{\circ}$ with the ground. At what height from the ground did the tree break?

Attached below is the diagram that I have drawn. Kindly check that along with what I've tried already.

[![Diagram](https://i.stack.imgur.com/8mdgv.jpg)](https://i.stack.imgur.com/8mdgv.jpg)

What I've tried,

Let $CD=x$ $m$

$\therefore$ $AC=(15-x)$ $m$

In $\triangle ACB$, we have:-

$tan$ ${60}^{\circ}$=$\frac{AC}{AB}$

$\sqrt3$=$\frac{15-x}{AB}$

But, I cant carry on further.