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Math Help - area and perimeter of parallelogram

  1. #1
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    area and perimeter of parallelogram

    hi,

    i have a parallelogram which is made up of of co ordinates which are, A(2,1) B(8.9) C(12,9) D(6,1):

    i have drawn the shape but i don't know how to work out the area and perimeter of it so i was looking for some help please.

    thanks!
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  2. #2
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    Quote Originally Posted by andyboy179 View Post
    parallelogram which is made up of of co ordinates which are, A(2,1) B(8.9) C(12,9) D(6,1)
    Area is \text{base}\times\text{height}.
    The base is \overline{AD}. What is the height?
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  3. #3
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    would the base = 4? because on the grid it is 4 block long?
    the height is not stated thats why im having problems.
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    The perimeter is easy- it is twice the size of the lengths of two adjacent sides. AB and AD are two such sides: their lengths are \sqrt{(8- 2)^2+ (9- 1)^2} and \sqrt{(6- 2)^2+ (1-1)^2}.

    The area of a parallelogram is "height times base". Fortunately two of the parallel sides are "horizontal"- parallel to the x-axis. The length of the base AD is the difference in x coordinates of A and D:6- 2= 4. The height is the difference in y-coordinates: 9- 1= 8.
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  5. #5
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    Quote Originally Posted by andyboy179 View Post
    would the base = 4? because on the grid it is 4 block long?
    the height is not stated thats why im having problems.
    Yes, the base is 4 units. How far is the point B from \overline{AD}~?
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    Quote Originally Posted by HallsofIvy View Post
    The perimeter is easy- it is twice the size of the lengths of two adjacent sides. AB and AD are two such sides: their lengths are \sqrt{(8- 2)^2+ (9- 1)^2} and \sqrt{(6- 2)^2+ (1-1)^2}.

    The area of a parallelogram is "height times base". Fortunately two of the parallel sides are "horizontal"- parallel to the x-axis. The length of the base AD is the difference in x coordinates of A and D:6- 2= 4. The height is the difference in y-coordinates: 9- 1= 8.
    would the perimeter be 70 and 4?
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  7. #7
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    Quote Originally Posted by Plato View Post
    Yes, the base is 4 units. How far is the point B from \overline{AD}~?
    90 degrees?
    Last edited by andyboy179; April 7th 2011 at 08:17 AM.
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  8. #8
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    Quote Originally Posted by andyboy179 View Post
    would the perimeter be 70 and 4?
    The perimeter is a single number!
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    Quote Originally Posted by andyboy179 View Post
    90 degrees?
    90 degrees measures an angle, not a distance!
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  10. #10
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    Quote Originally Posted by HallsofIvy View Post
    The perimeter is a single number!
    would i just add them together?
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  11. #11
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    Quote Originally Posted by HallsofIvy View Post
    90 degrees measures an angle, not a distance!

    okay. would it be 13
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    can someone confirm if this is correct so far?
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  13. #13
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    Plato or Hallsofivy for the area would I do 4 x 13=52???
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  14. #14
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    area and perimeter of parallelogram

    Hi andyboy179,
    You have drawn this shape on a grid and you should be able to find the lengths of the sides and you id a 4. So what is the length of a longer side,With this the perimeter is easy. Just add the four sides.You may be hung up on area so go back to your book or to internet to find out how to calculate area.The numbers are right there on your grid.


    bjh
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  15. #15
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    Would the area be:
    4x8=32?
    also for the perimeter would I just do 4+4+8+8=24?
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