This Instructional Activity is a part of the Lesson 10, Unit 3, Grade 7. Students use vertical angles, adjacent angles, angles on a line, and angles at a point in a multistep problem to write and solve simple equations for an unknown angle in a figure. In Lessons, students apply their understanding of equations to unknown angle problems. Students understand that the unknown angle is an actual, measureable angle; they simply need to find the value that makes each equation true.