It is: 180 degrees
Half of a revolution of a circle is 180 degrees and its angles added together are supplementary.
A right angle.
One forth of a revolution is 90 degrees or a right angle.
It is a right angle which is 90 degrees.
It is a right angle that measures 90 degrees
There is no specific name.
a revolution angle is exactly 360 deegres
To bisect an angle is to divide the angle in half.
One half of a right angle is a 45 degree angle.
The first angle that is half as large as the other angle is 30º The other angle that is the larger is 60º