Find the area of the triangle formed by joining the midpoints of the sides of the triangle 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 sq units