Scaling probability

Question

I've been asked to calculate the probability for there to be less than two dots on a $\frac{1}{2}m^2$. With the average being 10 dots per $m^2$.
I assumed that due to the discrete nature of the question, the distribution we need to use is a Poisson Distribution. That would give me $P(x \leq 2) = \sum_{0}^2 \frac{10^x e^{-10}}{x!} = 0.002769$
Now how would I use that to get the probability of getting two dots on half that size?