This Instructional Activity is a part of the Lesson 8, Unit 2, Grade 8. In this activity, students create triangles with given angles and compare them to classmates' triangles to see that they are not necessarily congruent, but they are similar. Each angle measure in a triangle imposes a constraint and students are examining in this activity how many constraints there are in similar triangles. There are only two. This makes sense since we can place one side of the triangle and then the triangle is determined by the length of that side and the two angles made with that side.