1. Finding the Area of Polygons Rectangles Parallelograms Triangles Trapezoids

2. Review: Perimeter Perimeter is the distance around a figure. To calculate perimeter, add up the lengths of the sides. Using your ruler, measure the perimeter of your rectangle.

3. What is the Perimeter of Your Rectangle? A.24 inches B.20 inches C.22 inches D.18 inches

4. Area Area is the amount of space a figure takes up. Area is measured in square units. Draw a grid on your rectangle so that you can count the number of square units.

5. What is the area of your rectangle? A.24 square inches B.20 square inches C. 22 square inches D.18 square inches

6. Can you think of an easier way to count the squares? If you multiply the number of squares going across times the number of square going down, you get 24. The formula for the area of a rectangle is: Area = Length x Width

7. Parallelogram Using scissors, cut a 45 degree diagonal line starting in one corner of your rectangle. Take the piece you cut off and move it to the other side. Now you have a parallelogram! What is the area of this parallelogram? Think: Have we changed the area?

8. Trapezoid See if you can make a trapezoid using the same 2 pieces. Have we changed the area?

9. Trapezoid Area Formula Average the lengths of the bases. To do this: 1. Add the lengths of the bases together. 2. Divide by 2. Multiply by the height. Did you get 24?

10. Triangle Cut your “original” rectangle in half diagonally to make 2 triangles. What do you notice about these 2 triangles?

11. A.They are congruent. B.They are right triangles. C.They are scalene triangles. D.All of the above are true.

12. Triangle Area Formula Every triangle is half of a parallelogram. Therefore, the formula is: Base x Height 2

13. 1) What formula should we use? A.bh B.½ bh C.½ (b1 +b2)h

14. 2) What formula should we use? A.bh B.½ bh C.½ (b1 +b2)h

15. 3) What formula should we use? A.bh B.½ bh C.½ (b1 +b2)h

16. 4) What formula should we use? A.bh B.½ bh C.½ (b1 +b2)h