Imagine you are standing in front of a big pizza. You want to share it with your friend, but they are standing on the other side of the pizza. You need to tell them what part of the pizza to take. The side closest to you or the other side? To tell them which part to take, you need to use a special word called "horizontal angle".
A horizontal angle is like a special way of measuring how far away something is on a flat surface. Instead of saying "take the left side of the pizza", you might say "take the part that is 90 degrees from where I am standing". This means your friend should go straight across from where you are standing to the other side.
Just like with a pizza, we can also use horizontal angles to talk about objects in the real world. For example, if you want to tell someone where a mountain is, you might say "look to the west at a horizontal angle of 45 degrees". This means they should turn to the left and look up a little bit.
So remember, when you hear the words "horizontal angle", it just means the special way of measuring how far away something is on a flat surface. It's like giving directions to a friend about where to take a slice of pizza, but for the real world!