0 or dot, depending on what course you are taking
When you have two squares stacked on top of each other, pretend the angle in the bottom left of the top square is a 90 degree angle, that means that the angle of the square right underneath, also sharing the line, is a 90 degree angle. Or whatever you would need to get it equal to 180, my example was 90/90.
9 X 9 X 20 X 20
Pido perdón para mí español, pero creo que este es la ecuación.
