# G.GCO.9 Acute Angles of a Right Triangle

- Author:
- Dan Dale, Tim Brzezinski

- Topic:
- Angles, Right Triangles

Interact with the applet below for a minute or two.
Then answer the questions that follow.
(Feel free to move the triangle's BIG WHITE VERTICES anywhere you'd like.)

## 1.

What is the sum of the measures of the 2 acute angles of any right triangle?

## 2.

Given your response to (1) above, what adjective can you use to describe the relationship between these 2 acute angles?

## 3.

Explain how/why this fact is an immediate result of the theorem you previously saw here (or here.)