Q13 of 157 Page 753

Show that the following points are collinear:

A(5, 1), B(1, –1) and C(11, 4)

To show that the points are collinear, we show that the area of triangle is equilateral = 0


Δ = 0


Δ = 1/2{x1(y2−y3) + x2(y3−y1) + x3(y1−y2)}


⇒ Δ = 1/2{5(–1– 4) + 1 (4– 1) + 11 (1 + 1)}


⇒ 1/2{–25 + 3 + 22}


= 0


Hence collinear


More from this chapter

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13

Show that the following points are collinear:

A(2, – 2), B(–3, 8) and C(–1, 4)

 13

Show that the following points are collinear:

A(–5, 1), B(5, 5) and C(10, 7)

 13

Show that the following points are collinear:

 14

Find the value of x for which the points A(x, 2), B(–3, –4) and C(7, –5) are collinear.