A 60 degree angle
90 - 30 = 60 degrees.
a 60-degree angle
Complementary angles add up to 90 degrees. So, 90 - 30 = 60. The complement of 30 degrees is 60 degrees. Supplementary angles have a sum (add up to) 180 degrees.
150 degrees
A right angle
90 degrees
60 degrees
15 degrees. A bisected 60 degree angle makes 2 30 degree angles by definition of an angle bisector, then a 30 degree angle makes 2 15 degree angles by definition of an angle bisector.
90 degrees
60 degrees
30 degree angle