1. This is an obtuse angle. It is more than 90 degrees, but less than 180 degrees.
2. Perpendicular would mean right angle, which equals 90 degrees.
3. An obtuse angle is greater than 90 and less than 180, so the answer would be 100 degrees.
4. An acute angle is less than 90 degrees, so the answer would be 28 degrees.
