Interior vs Exterior Math Example 1

Solution

1. 1
   Step 1: Identify the boundary. The circle has radius $r = 5$ cm, so the boundary is the set of all points exactly 5 cm from the center.
2. 2
   Step 2: Check Point $A$. Since $3 < 5$, Point $A$ is closer to the center than the radius, so it lies inside the circle — it is an interior point.
3. 3
   Step 3: Check Point $B$. Since $7 > 5$, Point $B$ is farther from the center than the radius, so it lies outside the circle — it is an exterior point.