👉 In geometry, a semi-angle is an angle whose measure is less than 90 degrees but greater than 45 degrees. This type of angle can be thought of as being "semi-infinite" or "halfway between two angles." For example, in a right triangle, if the angle at the right vertex is 30 degrees and the angle at the left vertex is 60 degrees, then the sum of these two angles (which are half of the total angle) will
