Does a semi circle have obtuse angles?

Answer 1

In geometry, angles are created by the intersection of lines or of line segments. A curve is not an angle, and a semi-circle (or complete circle) consists only of one continuous curve. There are no angles as such. If you like, you can conceive of a curve as a collection of infinitely many angles. But you can never see them individually, they are only seen as a group. They are not obtuse (or acute) angles in the normal sense of the term.