This is a exploration activity that uses a geoboard to investigate the areas and perimeters of parallelograms and triangles after an introduction by you (what to review/emphasize before students begin to work is included). Students use the geoboards to change the shape and size of these polygons and observe how their areas and perimeters change accordingly. A follow-up homework assignment is included. This is a nice hands-on activity that encourages cooperative learning, introduces new content, and reinforces old content (working with radicals, for example). It also opens the door for intelligent discussion between students about geometric figures. An answer key for the activity is included as well!