Question 660121: The points of the triangle are A(1, 10), B(8, 1), and C(13, 1).
How do I find the area of this triangle?
Found 2 solutions by Alan3354, MathLover1:
Answer by Alan3354(69443)   (Show Source):
You can put this solution on YOUR website! The points of the triangle are A(1, 10), B(8, 1), and C(13, 1).
How do I find the area of this triangle?
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There are several ways. You can find the length of 3 sides and use Heron's Law.
You can find 2 sides and the included angle, then Area = a*b*sin(angle)
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Do it like this.
A B C A
1 8 13 1
10 1 1 10
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Add the diagonal products starting upper left.
1*1 + 8*1 + 13*10 = 1 + 8 + 130 = 139
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Add the diagonal products starting lower left.
10*8 + 1*13 + 1*1 = 80 + 13 + 1 = 94
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The area is 1/2 the ABS of the difference
(139 - 94)/2 = 22.5 sq units
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That works for any polygon, and number of sides.
I think the coordinates have to be entered in order around the polygon.
Answer by MathLover1(20850)  (Show Source):
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