Question

what is the radius of this circle?

Explanation:

Step1: Observe the grid - based circle

By looking at the graph, we can count the number of grid - units from the center of the circle to its edge.

Step2: Determine the radius length

The center of the circle is at (1,1) and it touches the grid at (2,1). The distance between the center (1,1) and the point on the circle (2,1) is 1 unit.

Answer:

1