1. **State the problem:** We have a circle on a grid where each square measures 1 unit by 1 unit. We need to find: - The radius of the circle. - The diameter of the circle. - An estimate of the area of the circle using the grid. 2. **Radius:** The radius is the distance from the center of the circle to any point on its edge. From the problem, the circle spans 4 grid squares from the center to the edge, so the radius $r = 4$ units. 3. **Diameter:** The diameter $d$ is twice the radius. $$d = 2r$$ Substitute $r=4$: $$d = 2 \times 4 = 8$$ So, the diameter is 8 units. 4. **Area:** The area $A$ of a circle is given by the formula: $$A = \pi r^2$$ Substitute $r=4$: $$A = \pi \times 4^2 = \pi \times 16 = 16\pi$$ Using the grid, the area is approximately the number of full squares inside the circle plus partial squares. Since $16\pi \approx 50.27$, the area is about 50 square units. **Final answers:** - Radius = 4 units - Diameter = 8 units - Area $\approx 50$ square units