In geometry an angle is formed by what?
If you mean an angle then an angle is formed by two straight lines meeting at a vertex.
What is the name of the math symbol for an angle it looks similar to the greater than symbol but flat on the bottom?
An angle is formed by at least three points of reference. The origin and two others in plain geometry. A line may be drawn from the point of origin and any other given point. Any other line may be drawn from the origin and any other point. The difference between these lines is referred to as an angle.
The interior angle of a polygon is the angle formed by two adjacent sides of a polygon where the angle lies inside the area formed by the polygon. The exterior angle is that formed by one of these sides and the line formed by extending the other side. Consequently, External angle = 180 deg - Internal angle. Because they form supplementary angles, it does not matter which of the two sides you extend.