The length of focal chord to the parabola ${\mathrm{y}}^2=12\mathrm{x}$ drawn from the point (3, 6) on it is________.

a = 3 Comparing point (3, 6) with $\left(3{\mathrm{t}}^2,6\mathrm{t}\right)$, 

we have t = 1.Then Length of chord $\mathrm{a}{\left(\mathrm{t}+\frac{1}{\mathrm{t}}\right)}^2=3(1+1{)}^2=12$.