How many corners are there in a semi-circle?

Answer 1

In a circle, it is argued that there are either no corners, or infinitely many, depending upon the depth of the mathematics involved.

Given that a semi-circle is half a circle, then the arc must have either 0/2 = 0 or infinity/2 = infinity corners.
Where the arc connects with the diameter, there are unquestionably two corners, so the two values are:
0+2=2 or infinity+2=infinity
2 or infinity

Answer 2

2