Find the area of a quadrilateral ABCD, the coordinates of whose varities are A (-3, 2), B (5, 4), C (7, -6) and (-5, -4).
Area of triangle is given by 12|x1(y2−y3)+x2(y3−y1)+x3(y1−y2)|
Area of quadrilateral ABCD = Area of triangle ABC + Area of triangle ADC
=12|−3(4+6)+5(−6−2)+7(2−4)|+12|−3(−4+6)−5(−6−2)+7(2+4)|
=42+38=80 sq. units