This Instructional Activity is a part of the Lesson 17, Unit 7, Grade 7. Students combine their solid with a partner's and examine the new solid's properties. If there is time, this activity can be extended to review relationships between angles as well. Ask students what type of angle is created and what the relationship between the two angles creating that angle must be. Take three identical prisms and put them together so that a different angle from each prism is adjacent.