What is the area of the shape contained by the points A (0, 6), B (-2, 4), C (0, 2), and D (2, 4)?
The first thing we should do is draw this out. That'll give us a better sense of what this shape is other than the extremely unhelpful "quadrilateral."
Rather than using the distance formula to check whether the sides are of equal length, we can take a look at the diagonals. Each of the diagonals is 6 – 2 = 2 – (-2) = 4 units long, and is bisected by the other. At the very least, we have a rhombus.
We can use the area formula for a rhombus using the diagonals, setting d1 = d2 = 4 units.