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basic concepts area and perimeter PowerPoint Presentation
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basic concepts area and perimeter

basic concepts area and perimeter

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basic concepts area and perimeter

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  1. basic concepts area and perimeter

  2. Find the area of a rectangle whose dimensions are

  3. Find the area of a rectangle whose dimensions are 5  3 3 5

  4. Find the area of a rectangle whose dimensions are 5  3 3 5

  5. Find the area of a rectangle whose dimensions are 5  3 3 15 square units 5 It takes 15 1x1 tiles to cover the rectangle.

  6. Find the area of a rectangle whose dimensions are 5  3 W 3 15 square units 5 L It takes 15 1x1 tiles to cover the rectangle. Area = Length x Width A = LW

  7. Find the perimeter of a rectangle whose dimensions are 5  3 W 3 5 L

  8. “measure” Find the perimeter of a rectangle whose dimensions are 5  3 W 3 5 L

  9. “around” Find the perimeter of a rectangle whose dimensions are 5  3 W 3 5 L

  10. Find the perimeter of a rectangle whose dimensions are 5  3 W 3 5 5 L

  11. Find the perimeter of a rectangle whose dimensions are 5  3 W 3 5 + 3 5 L

  12. Find the perimeter of a rectangle whose dimensions are 5  3 W 3 5 + 3 + 5 5 L

  13. Find the perimeter of a rectangle whose dimensions are 5  3 W 3 5 + 3 + 5 + 3 5 L

  14. Find the perimeter of a rectangle whose dimensions are 5  3 W 3 5 + 3 + 5 + 3 5 L Perimeter = Length + Width + Length + Width P = 2L + 2W

  15. The DIAMETER is the measure across the circle

  16. The DIAMETER is the measure across the circle through the center

  17. The DIAMETER is the measure across the circle through the center The RADIUS is the measure from the center to any point on the circle The diameter = 2 times the radius d = 2r

  18. Wrap the diameter around the circle

  19. The diameter fits 3 times plus a little extra. The number  is the exact number of “diameters” needed to complete the circle.  is approximately 3.14

  20. The measure around the circle (perimeter) is called the circumference. The diameter fits 3 times plus a little extra. The number  is the exact number of “diameters” needed to complete the circle.  is approximately 3.14

  21. The measure around the circle (perimeter) is called the circumference. The circumference =  times the diameter. C =  d The diameter fits 3 times plus a little extra. The number  is the exact number of “diameters” needed to complete the circle.  is approximately 3.14

  22. The are of a circle is the number of square units needed to fill the circle. The following formula gives the area of a circle: A =  r 2 example: A circle whose radius is 3 units has area 9   28.26 square units <a href = http://www.education2000.com/demo/demo/botchtml/areacirc.htm ></a> Check the web page above to see a visual proof of the area formula

  23. example:

  24. The circumference of the circle is 10  What is the area of the shaded region?______

  25. The circumference of the circle is 10  What is the area of the shaded region?______ C =  d d = 10 r = 5 10

  26. The circumference of the circle is 10  What is the area of the shaded region?______ 10 the area of the square is 100

  27. The circumference of the circle is 10  What is the area of the shaded region?______ 5 10 - the area of the square is 100 the area of the circle is 25 

  28. The circumference of the circle is 10  What is the area of the shaded region?______ 5 (100 – 25 ) square units 100 – 78.5 = 21.5 square units 10 - the area of the square is 100 the area of the circle is 25 