1. Area of 2D shapes

2. Quadrilaterals A quadrilateral is a geometric figure that is made up of four line segments, called sides, that intersect only at their endpoints.

3. What are parallel lines? Two lines that never intersect.

4. Special Quadrilaterals Trapezoid – A quadrilateral with exactly 1 pair of parallel sides. Parallelogram – A quadrilateral with 2 pairs of parallel sides.

5. What is the area of this parallelogram? PARALLELOGRAM CUT HERE! S=side H=height B=base

6. What is the area of this parallelogram? PARALLELOGRAM MOVE TO HERE! B=base H=height

7. It’s the same as the area of this rectangle! PARALLELOGRAM H=height B=base

8. Area parallelogram = Base x Height (perpendicular height H) PARALLELOGRAM B=base Side H=height

9. To find the area of a parallelogram, you always multiply the base and the height. So, Area = base x height or A = bh Remember: The height is the line segment that is perpendicular to the base and creates a right angle. 12 in 10 in What is the area of this parallelogram? Area = base x height A = (10)(10) A = 100 in²

10. Your Turn Find the area and perimeter of the parallelogram. 12 cm 14 cm P = 12+12+14+14 P = 52 cm

11. Area of a Triangle 1 2 Area of parallelogram = base x height Area of triangle = base x height Area = bh

12. Finding the Area of a Triangle 1. Write the formula for area of a triangle. 2. Substitute in values. 3. Simplify. 11 ft 23 ft A= bh 11 A= (23)(11) A= 126.5 ft²

13. You try! Find the area and perimeter of the triangle. 17 m 13.4 m 20 m 15 m P = 20+15+17 P = 52 m

14. Given the formula for the area of a parallelogram we are going to use that information to discover the formula for the area of a trapezoid. Watch carefully not to miss it!

15. Notice that the trapezoid is half the area of the parallelogram. (b 1 + b 2 ) h Copy the trapezoid, flip it over, and put it next to the original. It makes a parallelogram. We are going to use the area of a parallelogram to find the area of a trapezoid. It takes two trapezoids to make one parallelogram.

16. (b 1 + b 2 ) h Parallelogram Trapezoid Notice that the trapezoid is half the area of the parallelogram. How do we find half the area ? A = (b 1 + b 2 ) h Hint: Think of area of a triangle.

17. Area of Trapezoid 2 in 6 in 3 in A = (b 1 + b 2 ) h 4 in A = (2 + 6) 3 A = (8) 3 A = 4 3 A = 12 in² 4 in Perimeter of Trapezoid P = 4 + 4 + 2 + 6 P = 16 in

18. Area of Trapezoid 3 m 8 m 4 m 5 m A = (b 1 + b 2 ) h A = (3 + 8) 4 A = (11) 4 A = (44) A = 22 m²

19. Practice!