Circles Math Example 1

Solution

1. 1
   Key circle relationships: the diameter $d$ spans the full width through the centre, so $d = 2r$. The radius $r$ is the distance from centre to any point on the circle, so $r = \frac{d}{2}$.
2. 2
   Substitute $r = 7$ cm into $d = 2r$: $d = 2(7) = 14$ cm.
3. 3
   Verify the relationship: $r = \frac{d}{2} = \frac{14}{2} = 7$ cm ✓. The diameter is always exactly twice the radius regardless of the circle's size.