Find the area of the triangle formed by joining the mid points of the sides of the triangle formed with coordinates A (-4, 3), B (2, 3) and C (4, 5).
1.5
The mid points of AB, BC and CA are (−4+22, 3+32), (4+22, 3+52) and (−4+42, 5+32) respectively and lets denote them as D, E and F. So D(-1, 3), E(3, 4) and F(0, 4).
Suppose x1 = -1, y1 = 3
x2 = 3, y2 = 4
x3 = 0, y3 = 4
Area of a triangle =12[x1(y2−y3)+x2(y3−y1)+x3(y1−y2)]
= 12[ -1(4 - 4) + 3(4 - 3) + 0(3 - 4)]
= 1.5
Area of a triangle = 1.5