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Question
Find the area of Δ ABC whose vertices are:
A (1,2) B (-2,3) and C (-3,-4)
Solution
A (1,2) B (-2,3) and C (-3,-4) are the vertices of . ΔABC Then,
`(x_1 =1,y_1=2),(x_2=-2,y_2=3) and (x_3=-3,y_3=-4)`
Area of triangle ABC
`=1/2 {x_1(y_2-y_3)+x_2(y_3-y_1)+x_3(y_1-y_2)}`
` = 1/2 { 1(3-(-4))+(-2)(-4-2) + (-3)(2-3)}`
`=1/2 { 1(3+4)-2(-6) -3 (-1)}`
`=1/2 {7+12+3}`
`=1/2 (22)`
= 11 sq. units
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