Question

what is the radius of this circle?

Explanation:

Step1: Observe the grid - size

Each grid represents 1 unit.

Step2: Determine the circle's feature

The circle appears to have a diameter of 2 grid - units.

Step3: Calculate the radius

The radius $r$ of a circle is half of its diameter $d$. Since $d = 2$, then $r=\frac{d}{2}=\frac{2}{2}=1$.

Answer:

1