# Circumcenter & Circumcircle (A)

Interact with this applet for a few minutes, then answer the questions that follow. Be sure to change the locations of the triangle's

**PINK VERTICES**before and after sliding the slider!1) What can you conclude about the 3 white points? How do you know this?

2) What is the measure of each **gray angle**? How do you know this?

3) What vocabulary terms best describes each **brown dotted line**? Why is this?

4) Describe **the intersection** of these **3 brown dotted lines**. **How do they intersect?**

5) Use the angle tool to now measure and display the measures of this triangle's 3 interior angles. For angle measures > 180 degrees, use the menu (upper right hand corner) to adjust this.

**Point C**is called the

**circumcenter**of the triangle. Drag the

**pink vertices**around to help you answer the new few questions.

6) What is so special about the **green circle** with respect to the triangle's **pink vertices**?