SOLUTION: Find the area of a triangle PQR, where P=(4,4,−1), Q=(3,3,1), and R=(3,−5,6)

Algebra ->  Vectors -> SOLUTION: Find the area of a triangle PQR, where P=(4,4,−1), Q=(3,3,1), and R=(3,−5,6)      Log On


   

Question 1141440: Find the area of a triangle PQR, where P=(4,4,−1), Q=(3,3,1), and R=(3,−5,6)
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
Find the area of a triangle PQR, where P=(4,4,−1), Q=(3,3,1), and R=(3,−5,6)
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A = PQ = (1,1,-2)
B = QR = (0,8,-5)
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Find the cross product of AB

|i   j   k|
|1   1  -2|  ---> 11i + 5j + 8k = C
|0   8  -5|

Magnitude of C = sqrt%2811%5E2+%2B+5%5E2+%2B+8%5E2%29+=+sqrt%28210%29
Mag of C = area of parallelogram formed by A & B
Area of triangle is 1/2 of that
Area = sqrt%28210%29%2F2 sq units
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I haven't done one of those in decades.
I think that's right.