By plotting the points A(2,5), B(−2,2), and C(4,2) on graph paper, and Joining AB, BC, and AC in the graph. Calculate the area of the ΔABC by using the graph. 

Construct a line  AM from point A, which is perpendicular to BC.

So, AM = 5 - 2 = 3

And, BC = 4 - (-2) = 6

Area of ΔABC = $\frac{1}{2} \times \mathrm{b} \times \mathrm{h} = \frac{1}{2 } \times \mathrm{BC} \times \mathrm{AM}$

Area of ∆ABC = $\frac{1}{2} \times 6 \times 3$   

​Area of ∆ABC = 9 sq. units