1. **Problem:** Can you draw a circle and show its radius? 2. **Formula:** The radius is the distance from the center to the edge of the circle. $r=\frac{d}{2}$ If the diameter is known, you can find the radius by dividing by $2$. 3. **Example:** If the diameter is $10$, then $r=\frac{10}{2}$ $r=5$ So the radius is $5$. 4. **Drawing:** The circle below shows the center and a radius segment. 5. **Final answer:** The circle is drawn with a radius labeled $5$.