(Q6) Find the area of a triangle whose vertices are (1,-1),(-4, 6) and (-3, -5).

Area of the triangle = ∆ =
1
2
 |x1(y2-y3)+x2(y3-y1)+x3(y1-y2)|

The area of a triangle formed by the vertices A(1,-1),B(-4,6) and C(-3,-5),by using the formula

∆ =
1
2
 |1(+)+(-4)(-+)+(-3)(--)|
 =
1
2
 ||=

So the area of the triangle is square units.