This Instructional Activity is a part of the Lesson 22, Unit 3, Grade 7. Students find the surface area of three-dimensional objects whose surface area is composed of triangles and quadrilaterals, specifically focusing on pyramids. They use polyhedron nets to understand that surface area is simply the sum of the area of the lateral faces and the area of the base(s). Make copies of the composite figure on cardstock and have students cut and fold the net to form the three-dimensional object.