Find the rate in which both balls make one full rotation around the track.
Ball A:

It takes 30 seconds for Ball A to make a full rotation.
Ball B:

It takes 20 seconds for Ball B to make a full rotation.
Find the least common multiple of 20 and 30 to find the time at which they'll meet.
Multiples of 20: {20,40,60}
Multiples of 30: {30,60}
60 is the least common multiple of both 20 and 30.
The balls will meet again at
60 seconds.
4.5 x 10^6 = 4,500,000
2.1 x 10^8 = 210,000,000
Therefore, 4.5 x 10^6 < 2.1 x 10^8
Answer:
a
Step-by-step explanation:
Answer:
40°
Step-by-step explanation:
Measure of Nonagon (9-sided polygon) = 1260°
Each angle measure = 1260 ÷ 9 = 140°
The value of x (the outside angle) = 180° - 140° = 40°