The length of one revolution determines how long their___________ are.

periods are.

The length of one revolution determines how long their **periods** are.

The length of one revolution determines how long their "cycles" are.

To understand why, let's break it down:

1. A revolution refers to one complete turn or rotation around a central point. It can apply to various scenarios, such as the orbit of planets around the sun or the spinning of an object on its axis.

2. When we talk about "cycles," we are referring to a repeating pattern that occurs within a given time frame. Cycles can represent events or phenomena that happen over and over again.

3. The length of one revolution directly influences the duration of the cycles associated with that revolution. In other words, as the length of a revolution changes, the time it takes for a particular cycle to complete also changes.

For example:
- If we consider the Earth's revolution around the sun, which takes approximately 365.25 days (one year), it determines the length of various cycles on Earth. These cycles include the seasons, as the Earth's tilt and its position in its orbit affect the amount of sunlight different regions receive throughout the year.

- If we look at a spinning top, one complete revolution determines the length of its rotational cycle. The time it takes for the top to complete one full rotation determines the length of that cycle.

So, depending on the context, the length of one revolution determines how long the associated cycles are.