SOLUTION: Find its area. A = (-2, 5); B = (1, 3); C = (-1, 0)

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Question 491981: Find its area.
A = (-2, 5); B = (1, 3); C = (-1, 0)

Answer by cleomenius(959) About Me  (Show Source):
You can put this solution on YOUR website!
We will use the distance formula to find the distance between vertices.
sqrt%28%28x2+-+x1%29%5E2+%2B+%28y2+-+y1%29%5E2%29
AB = sqrt%28%281+-+-2+%29%5E2+%2B+%283+-+5%29%5E2%29
AB = sqrt%28%283%29%5E2+%2B+%282%29%5E2%29
AB = sqrt%2813%29
==========================================
BC = sqrt%28%28-1+-+-1%29%5E2+%2B+%280+-+3%29%5E2%29
BC = sqrt%28%282%29%5E2+%2B+%283%29%5E2%29
BC = sqrt%2813%29
==========================================
AC = sqrt%28%28-1+-+-2%29%5E2+%2B+%280+-+5%29%5E2%29
AC = sqrt%28%281%29%5E2+%2B+%285%29%5E2%29
AC = sqrt%2826%29
Ac = sqrt%282%29sqrt%2813%29
==========================================
At this point, I converted to decimals, they are easier to work with.
AC = 3.6
BC = 3.6
AC = 5.1
============================================
Now, we use Herons formula to find the area.
Area = sqrt%28s%28s-a%29%28s-b%29%28s-c%29%29
s = (3.6 + 3.6 + 5.1) / 2
s = 12.3/ 2 =6.15
Area = sqrt%286.15%29%282.55%29%282.55%29%281.05%29%29
Area = sqrt%2819.28%29
Area = 4.4
Cleomenius.