To find the radius of the dilated circle when you scale up by a factor of 50, you simply multiply the original radius by that factor.
The original radius of the circle is 2 mm. Therefore, when dilated by a factor of 50:
\[ \text{Dilated radius} = \text{Original radius} \times \text{Scale factor} = 2 , \text{mm} \times 50 = 100 , \text{mm} \]
So, the radius of the dilated circle will be 100 mm.