Use informal arguments to establish facts about the angle sum and exterior angle of triangles, about the angles created when parallel lines are cut by a transversal, and the angle-angle criterion for similarity of triangles.

### General Information

**Subject(s):**Mathematics

**Grade Level(s):**8

**Freely Available:**Yes

**Keywords:**Find the Angle, Angle, Find, cpalms, icpalms, illustrativemathematics.org, illustrative mathematics, tasks, mathematics, math, Florida standards, resource, free, freely available, problems-based learning, student activities

**Instructional Component Type(s):**

**Problem-Solving Task**

**Resource Collection:**Illustrative Mathematics