What You Did
You built a mariner’s quadrant.
Your quadrant should help you measure the height of very tall objects.
In my first trial of this craft, I chose plastic lacing for my string, because it had a pretty rainbow color, but it was too stiff. Make sure you choose a string that swings freely and is easily flexible.
Take your quadrant on a trip to a city, and see if you can measure skyscrapers
taking measurements, research methods