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| − | This formula finds the area of any 2-D figure whose coordinates of the vertices are known and the order in which the vertices are connected
| + | #REDIRECT [[Shoelace Theorem]] |
| − | given coordinates (in order) (A,B) (C,D) ...
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| − | You stack them vertically until you reach the first vertex make sure you list 1st vertex again at the bottom.
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| − | For a quadrilateral, this step would look like
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| − | A B
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| − | C D
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| − | E F
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| − | G H
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| − | A B
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| − | Now you find cross products. First all the diaonally down to the left. This would mean BC, DE, FG, and HA. Then these are added.
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| − | Then diagonally to the right. This would mean AD, CF, EH, and GB. These are also added.
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| − | the area is half of the positive difference between the sums
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