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10.1 area of polygons 1
- 1. 10.1 Area ofPolygons Page 521
- 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. 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
- 5. 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
- 6. Area Steps: 1. Write the area formula 2. Substitute the values given 3. Answer
- 7. Area of aparallelogram A=bxh height 90º base
- 8. What is thearea of this parallelogram? A=bxh height 5 cm. A=5x7 A = 35 cm2 base 7 cm. Perimeter P= 5 + 7 + 5 + 7 = 24 cm
- 9. What is thearea of this parallelogram? A=bxh 5 ft. A=5x6 6 ft. A = 30 ft2 8 ft. Perimeter P= 6 + 8 + 6 + 8 = 28 ft
- 10. What is thearea 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
- 11. Area of atrapezoid base 1 • Area = (b1 +b2) x h height 2 base 2
- 12. Area of atrapezoid • Area = (b1 +b2) x h base 1 base 2 2 height
- 13. What is thearea of this trapezoid? • Area = 15 inches (b1 +b2) x h 2 • Area = 8 Inches 12 (15 +7) x 8 7 inches 2 Perimeter P= 7 + 15 + 12 + 12= 46 in A= 88 in. sq.
- 14. GUIDED PRACTICE for Examples 1 and 2 2. 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.
- 15. What is thearea of this trapezoid? • Area = 25 (b1 +b2) x h 2 35 15 20 • Area = cm (20 +35) x 15 2 Perimeter A= 412.5 cm sq. P= 35 + 25 + 20 + 25= 105 cm
- 16. How to findthe area of a square or rectangle. Step 1 – Multiply the length times the width. (A = l x w) 5 3 cm. x3 15 cm 2 Perimeter 5 cm. P= 3 + 5 + 3 + 5= 16 cm
- 17. What is thearea? A=bxh 2 in. 2 6 in. x6 12 in. 2 Perimeter P= 2 + 6 + 2 + 6 = 16 in
- 18. TRIANGLES Area formula for triangles is A=bxh or ½ b (h) 2 h b
- 19. What is thearea of this triangle? Area = b x h 2 Area = 20 x 20 20 in 2 20 in A= 200 in. sq.
- 20. What is thearea of this triangle? Area = b x h 2 Area = 5 x 10 5 in 2 10 in A= 25 in. sq.
- 21. What is thearea of this triangle? Area = b x h 2 Area = 10 x 8 2 10 in A= 40 in. sq. 8 in
- 22. Find the area and perimeter: Area = b x h 9 cm 12 cm 2 8 Area = 18 x 8 2 18 cm A= 72 cm sq. P= 9 + 12 + 18 = 39 cm
- 23. 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.