Let’s start out by forgetting about numbers completely (you have too much of that with math already). Instead, let’s look at something very ordinary. Below you see a picture of a stick lying on the ground.
Drag the green handle attached to the stick and raise or lower it to different angles. You can also click at the place you want the stick to go to.
Pay attention to the shadow that the stick casts on the ground and on the “wall” as you move it.
Real world alert! Wait a minute...how come the shadow on the ground never gets longer than the stick, like it does in real life?
In the picture above, the light for the ground shadow is coming from directly overhead, and the light for the wall shadow comes from the left wall. (This is a computer. We can make the light come from anywhere we want to.) When you’re outside, say, in the late afternoon, the sun isn’t directly overhead, so everything changes. We’ll get to that in a page or two.
If you want to try this experiment in real life, do it near noontime, when the sun is directly overhead. The ground shadow will work pretty much the way it does here.