1. Geometry 7.1 Area of Triangles and Quadrilaterals

2. December 2, 2015 MA 08 Geometry 7.1 Areas of Triangles and Quadrilaterals Goals: Find the area of triangles, parallelograms, rectangles, squares, and trapezoids.

3. December 2, 2015 MA 08 Geometry 7.1 Areas of Triangles and Quadrilaterals Area The measure of part of a plane surface. Measured in square units. 10 square inches can be written 10 in 2.

4. December 2, 2015 MA 08 Geometry 7.1 Areas of Triangles and Quadrilaterals

5. December 2, 2015 MA 08 Geometry 7.1 Areas of Triangles and Quadrilaterals Area of a Square s s

6. December 2, 2015 MA 08 Geometry 7.1 Areas of Triangles and Quadrilaterals Area of a rectangle L W

7. December 2, 2015 MA 08 Geometry 7.1 Areas of Triangles and Quadrilaterals Area of Parallelogram h b

8. December 2, 2015 MA 08 Geometry 7.1 Areas of Triangles and Quadrilaterals Area of Parallelogram b h L W

9. December 2, 2015 MA 08 Geometry 7.1 Areas of Triangles and Quadrilaterals Area of a Triangle h b Why does this work?

10. December 2, 2015 MA 08 Geometry 7.1 Areas of Triangles and Quadrilaterals Area of a Triangle h b Make a congruent triangle.

11. December 2, 2015 MA 08 Geometry 7.1 Areas of Triangles and Quadrilaterals Area of a Triangle h b Rotate it 180 .

12. December 2, 2015 MA 08 Geometry 7.1 Areas of Triangles and Quadrilaterals Area of a Triangle h b Slide them together.

13. December 2, 2015 MA 08 Geometry 7.1 Areas of Triangles and Quadrilaterals Area of a Triangle h b This is just a parallelogram. The triangle is 1/ 2 of this.

14. December 2, 2015 MA 08 Geometry 7.1 Areas of Triangles and Quadrilaterals Which triangle has the largest area? A B C They all have the same area: equal bases and equal heights.

15. December 2, 2015 MA 08 Geometry 7.1 Areas of Triangles and Quadrilaterals Area of a Trapezoid b1b1 b2b2 h