This Problem Set is a part of the Lesson 11, Unit 6, Grade 7. Students understand that three given lengths determine a triangle, provided the largest length is less than the sum of the other two lengths; otherwise, no triangle can be formed. Students understand that if two side lengths of a triangle are given, then the third side length must be between the difference and the sum of the first two side lengths. Students understand that two angle measurements determine many triangles, provided the angle sum is less than 180°; otherwise, no triangle can be formed.