This Problem Set is a part of the Lesson 4, Unit 5, Grade 6. Students construct the altitude for three different cases: an altitude that is a side of a right angle, an altitude that lies over the base, and an altitude that is outside the triangle. Students deconstruct triangles to justify that the area of a triangle is exactly one half the area of a parallelogram. Students need the attached templates, scissors, a ruler, and glue to complete the Exploratory Challenge.