# What "CO" in COsine Means

- Author:
- Tim Brzezinski

Take a few minutes to interact with the applet below.
Then, answer the questions that follow.

In the right triangle above, what is the relationship between the **blue angle** and **pink angle**?
(What vocabulary term/adjective describes the relationship between these 2 angles?)

Fill in the blank with the correct word:
The _____________ of the **blue angle** is the **percentage displayed. **

Fill in the blank with the correct word:
The ___________________ of the **pink angle** is the **percentage displayed. **

Thus, we can conclude that if 2 angles are ______________________ (see your answer to (1)), then the __________ of **one angle** is equal to the ____________________ of its **___________________ **!
Notice how the first 2 letters of the last 2 blanks are the same? Why is this?