# IM2.7 T7: Inscribed Triangles, Circumscribed Angles

- Author:
- Lind, Jon

The triangle on the left has an inscribed circle. You learned how to do this in our triangle investigations earlier this year. Construct an inscribed circle in each of the other triangles.

## Circumscribed Angle

## 2 things about tangents

All of the triangles above represent three circumscribed angles, formed by two tangents to a circle. A. Think about the way you constructed your circles, and try to come up with a way to calculate the size of angle ABC above if I tell you that arc AC is 120°. Describe your method in words. B. What do you know about segments AB and BC?