Learn the concepts of area and perimeter and formulate strategies for estimating attributes.

Grades 2-4.

**Introduction**
The concepts of area and perimeter are key to understanding the relative size of objects when their attributes are changed. Students will explore this concept by calculating and comparing the area and perimeters of different figures. Students will also gain an appreciation for being able to view shapes from multiple angles while doing their calculations.
**Procedure**
The teacher should have students complete the Area and Perimeter worksheet using GollyGee Blocks in the Birds-Eye camera view (2D) mode and using the small size cube.

Students should rotate the GollyGee Blocks scene to view a 3D perspective and make journal entries on their observations from using 2D and 3D perspectives. Discuss what they observed.

Print out scenes and compare the different types of arrangements made by the class in both 2D and 3D views.

Repeat the exercise using the medium and large size cubes. There are three sizes of shapes available in the proportions 1:1:1, 2:2:2, and 3:3:3. What is the difference each size block does to the figure perimeter and area? Discuss conclusions.
**Evaluation**
The teacher should assess younger students using question and answer techniques on their comparisons and conversations about viewing shapes in 2D and 3D.

The worksheet can be graded for this activity.

Group discussions can also help the teacher assess student understanding. Encourage all students to participate in the discussions through question and answer techniques and asking the students to defend their answers with logic and reasoning.
**Extensions**
Models of the 3D objects can be made with construction paper and physically reproduced and compared to ones made with the computer.

Calculate the volumes of the objects on the worksheet.

The students should be encouraged to build their own figures and do perimeter and area calculations. Multi-level figures should be encouraged. Student-developed measurement tools can be constructed and used to do comparisons. Discussion on the relative merits of these tools should be held.

In conjunction with the Graphing activity, do area and perimeter comparisons.

Students should be encouraged to estimate calculations on a chart and then use measurement tools to do a more precise measurement. Compare the results and discuss.

Try doing object measurement comparisons in 2D and 3D and compare what happens when rotation and translation are available.
**Tips**
The wire frame mode is also useful in seeing through objects. Turn on the Grid mode tool so that objects will snap onto the grid with greater ease. The Stack tool should be turned on when doing more complex shapes. Students may also make their own shape proportion by using the ? tool.