Let the height of parallelogram taking AB as base be h.
Now, AB = √[(7-4)2 + (2+2)2]
AB = √(32 + 42) = 5 units
Area (Δ ABC) = ½[4(2 - 9) + 7(9 + 2) + 0(-2 - 2)]
Area (Δ ABC) = 49/2 sq units
Now, ½ × AB × h = 49/2
½ × 5 × h = 49/2
h = 49/5
h = 9.8 units