Question #5ec05

1 Answer
Jul 4, 2016

#10# sq. units.

Explanation:

Let #(x_1, y_1), (x_2, y_2) and (x_3, y_3)# be the co-ordinates of the vertices #A, B, C# respectively of the triangle #ABC#. Then area
#Delta ABC = 1/2| x_1 (y_2 - y_3) + x_2 (y_3 – y_1) + x_3 (y_1 – y_2) | #sq. units.

Given #(-2, 1), (1, 3) and (5, -1)#
#:. Delta ABC =1/2| -2(3- (-1)) + 1 (-1 – 1) + 5 (1 – 3)|#
#=> Delta ABC = 1/2| -2(4) + 1 (-2) + 5 (– 2)|#
#=> Delta ABC = 1/2| -8 -2 – 10|#
#=> Delta ABC = 10# sq. units.