Geometry

We can use a really handy formula to help solve this question. 

First, we have to calculate the semiperimeter of the triangle, which is half the sum of the three side.

We get $\frac{3+4+6}{2}=\frac{13}{2}$

That may seem useless, but it will come in handy very soon. 

Now, we apply Heron's Formula, which states that the area of a triangle is equal to $\sqrt{s(s-a)(s-b)(s-c)}$. Subbing everything in, We get

$Area = \sqrt{\frac{13}{2}(\frac{13}{2}-3)(\frac{13}{2}-4)(\frac{13}{2}-6)}$

$Area = \sqrt{\frac{455}{16}}=\frac{\sqrt{455}}{4}$

So our final answer is $\frac{\sqrt{455}}{4}$

Thanks! :)