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# 10.1 area of polygons 1

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### 10.1 area of polygons 1

1. 1. 10.1 Area of PolygonsPage 521
2. 2. Essential Questions How do you know when to find circumference or area? What strategies and formulas can you use? How is surface area used in the real world? How is the volume of a pyramid related to the volume of a box? How is the volume of a cone related to the volume of a cylinder?
3. 3. Area and Perimeter Perimeter-The distance around a polygon (the sum of the length of all sides) Area- The number of square units inside a closed figure
4. 4. Formulas Triangle: b x h or 1/2bh 2 Rectangle: A = l x w Square: A = l x w or s2 Parallelogram: A = b x h Trapezoid: (b1 +b2) x h or ½ (b1 +b2)x h 2
5. 5. Area Steps: 1. Write the area formula 2. Substitute the values given 3. Answer
6. 6. Area of a parallelogramA=bxh height 90º base
7. 7. What is the area of this parallelogram? A=bxh height 5 cm. A=5x7 A = 35 cm2 base 7 cm. Perimeter P= 5 + 7 + 5 + 7 = 24 cm
8. 8. What is the area of this parallelogram? A=bxh 5 ft. A=5x6 6 ft. A = 30 ft2 8 ft. Perimeter P= 6 + 8 + 6 + 8 = 28 ft
9. 9. What is the area of this parallelogram? 12 m. A=bxh A = 10 x 5 10 m. 5 m. A = 50 m2 Perimeter P= 5 + 12 + 5 +12= 34 m
10. 10. Area of a trapezoid base 1 • Area = (b1 +b2) x h height 2 base 2
11. 11. Area of a trapezoid • Area = (b1 +b2) x hbase 1 base 2 2 height
12. 12. What is the area of this trapezoid? • Area = 15 inches (b1 +b2) x h 2 • Area = 8 Inches 12 (15 +7) x 8 7 inches 2PerimeterP= 7 + 15 + 12 + 12= 46 in A= 88 in. sq.
13. 13. GUIDED PRACTICE for Examples 1 and 22. A trapezoid with bases of 14 feet and 17 feet and a height of 6 feet 1 A= (b + b2)h Write formula for area of a trapezoid. 2 1 1 A= (14 + 17)6 Substitute values for b1, b2 and h. 2 = 93 square feet Multiply.
14. 14. What is the area of this trapezoid? • Area = 25 (b1 +b2) x h 2 35 15 20 • Area = cm (20 +35) x 15 2Perimeter A= 412.5 cm sq.P= 35 + 25 + 20 + 25= 105 cm
15. 15. How to find the area of a square or rectangle. Step 1 – Multiply the length times the width. (A = l x w) 5 3 cm. x3 15 cm 2Perimeter 5 cm.P= 3 + 5 + 3 + 5= 16 cm
16. 16. What is the area? A=bxh 2 in. 2 6 in. x6 12 in. 2PerimeterP= 2 + 6 + 2 + 6 = 16 in
17. 17. TRIANGLES Area formula for triangles is A=bxh or ½ b (h) 2 h b
18. 18. What is the area of this triangle? Area = b x h 2 Area = 20 x 2020 in 2 20 in A= 200 in. sq.
19. 19. What is the area of this triangle? Area = b x h 2 Area = 5 x 10 5 in 2 10 in A= 25 in. sq.
20. 20. What is the area of this triangle? Area = b x h 2 Area = 10 x 8 210 in A= 40 in. sq. 8 in
21. 21.  Find the area and perimeter:Area = b x h 9 cm 12 cm 2 8Area = 18 x 8 2 18 cmA= 72 cm sq. P= 9 + 12 + 18 = 39 cm
22. 22.  Find the area and perimeter: Area = b x h 2 Area = 8 x 7 15 in 8 in 10 in 2 7 in A= 28 in. sq.P= 10 + 15 + 7 = 32 in.