Building the catapult involved taking many measurements to find how to make the catapult go as far as it could possibly throw a soft ball. To get the furthest distance we had to measure our catapult at an angle of 45 degrees. That would allow us to reach a farther distance than if the catapult were set at any other angle. Later, we added bungee cords, but knew that the more tension on the catapult the further the ball would fly.
We took measurements of every PVC pipe used and every piece of wood. Brenda and I wanted the symmetry with our catapult, not only a good distance shot.