Checkpoint 3 Answers

1. `40 pi ~~ 126` seconds, or `2` minutes, `6` seconds.
   `20 pi ~~ 63` seconds, or `1` minute, `3` seconds.
   `10 pi ~~ 31` seconds.

2. `10 pi ~~ 31` seconds.
   `(20 pi)/3~~21` seconds.

3. `theta=t/20.`

4. `x = 100` cos `(t/20)` and `y=100` sin `(t/20).`