Plot the points A(2, 5), B(–2, 2) and C(4, 2) on a graph paper. Join AB, BC and AC. Calculate the area of ΔABC.

Let the three vertices of triangle ABC be:


A (2, 5), B (-2, 2) and C (4, 2)


 


Now, when we plot these points in the graph paper then we see that,


 



 


Point A and C lie in the quadrant I and point B lie in the II quadrant


 


Let the line BC intersect y-axis at point D


 


∴ BC = (BD + DC)


 


= (2 + 4) units


 


= 6 units


 


Now, we have to draw AM perpendicular to x-axis and intersect BC at L


 


∴ Ordinate of point L = Ordinate of point B - Ordinate of point C


 


AL = AM – LM


 


= 5 – 2


 


= 3 units


 


Hence, Area of triangle ABC =


 


=


 


=


 


= 9 square units


 


∴ Area of triangle ABC = 9 square units


 

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