I am asked to find the area D. Since the traingle is displaced by "a" steps on the y-axis, I should be able to get the same area if I bring the triangle down to the x-axis, so that the bottom of the triangle is adjacent to the x-axis. My answer is wrong anyways, as the book says the area D is e^3. Where did I go wrong?

Not asking for a solution, just want some guidance. /wsr/ is dead as hell. Sorry for being a brainlet.