Hey there! I'm happy to help!
The distance around a circle is the circumference. To find it, you multiply the diameter of the circle by pi (we will use 3.14).
First, let's find the circumference of Nathan's circle. We see that the radius is 29. The diameter is twice the radius, so the diameter is 56. We multiply this by 3.14, giving us 175.84 m.
We see that Rachel is 2.5 m further from the center than Nathan's, so her radius is 31.5 m. We multiply by two to give us the diameter, giving us 63. We multiply this by 3.14, giving us 197.82.
Now, we subtract Nathan's lap distance from Rachel's to see how much longer her's is.
197.82-175.84=21.98
Therefore, the distance Rachel runs is 21.98 meters longer than the distance Nathan runs.
Have a wonderful day! :D