Answers:
If an angle is labeled with a single letter, that letter represents the vertex of the angle.
If more than one angle has the same vertex, you must use 3 points to name the angle. The middle point named must be the vertex.
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Explanation:
If we have a single triangle, and no other extra lines, then we can use single letters to name the three angles. Each vertex of the triangle corresponds to the vertex of that angle.
If you were to draw many triangles, in which some may or may not overlap, you'll mostly likely need to name the angle using 3 letters. This is so you are very specific about which angle you're talking about. The middle letter is always the vertex. The left and right letters are points on the arms of the angle. The order of the left and right letters doesn't matter as long as the middle letter stays the same. So something like angle ABC is the same as angle CBA.
