What is The area of a triangle whose vertices are j (-2,1), k (4,3) and l (-2,-5)?

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Answer 1 · 2018-04-23T17:00:35

# 18#.

Recall that, the Area #Delta# of #DeltaABC# with vertices

#A(x_1,y_1), B(x_2,y_2) and C(x_3,y_3)# is given by,

#Delta=1/2|D|#, where,

#D=|(x_1,y_1,1),(x_2,y_2,1),(x_3,y_3,1)|#,

In our case, #D=|(-2,1,1),(4,3,1),(-2,-5,1)|#,

#=-2{3-(-5)}-1{4-(-2)}+1{-20-(-6)}#,

#=-16-6-14#,

#=-36#.

# rArr Delta=18#.