Question

Find the area of the triangle whose vertices are A(1, 2), B(–2, 3) and C(–3, –4)

(a) 11sq. units (b) 22 sq. units (c) 7 sq. units (d) 6.5 sq. units

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Answer 1

We have :-

x1 = 1 y1 = 2

x2 = -2 y2 = 3

x3 = -3 y3 = -4

Area of Triangle ABC

= 1/2 [ x1 { y2 - y3 } + x2 { y3 - y1 } + x3 { y1 - y2 } ]

= 1/2 [ 1 { 3 - (-4) } + (-2) { -4 - 1 } + (-3) { 2 - 3 } ]

= 1/2 [ 1 { 3 + 4 } -2 { -5 } -3 { -1 } ]

= 1/2 [ (1 x 7) + 10 + 3 ]

= 1/2 [ 7 + 10 + 3 ]

= 1/2 [ 20]

= 10 sq. units