Find the area enclosed by the equation |x| + |y| = 4.
Given equation, we can write like:
If x < 0 and y > 0, - x + y = 4
If y < 0 and x> 0, x - y = 4
If x < 0 and y < 0, - x - y = 4
If x > 0 and y > 0, x + y = 4
From the above four equations, we can draw below graph.
Above graph is combination of 4 triangle. Area of one triangle = 12×base×height
=12×4×4=8
There are four similar triangle, Area = 8 × 4 = 32.