Draw a quadrilateral in the Cartesian plane, whose vertices are (– 4, 5), (0, 7), (5, – 5) and (– 4, –2). Also, find its area.


Let ABCD be the given quadrilateral with vertices A(-4,5) , B(0,7), C(5.-5) and D(-4,-2). Plotting the points on the Cartesian plane and joining AB, BC, CD, AD gives us the required quadrilateral.



To find the area, draw diagonal AC


area (ABCD) = ar ( ∆ABC) + ar(∆ADC)


area ∆ with vertices ( x1,y1) , (x2, y2) and (x3,y3) is



unit2


unit2



Area ∆ ACD =




Since area cannot be negative area ∆ ACD =


Area (ABCD) =


2
1