The measure of an angle is defined as the amount of rotation needed to bring one ray of the angle into alignment with the other ray. Angles are measured in degrees or radians. Commonly, angles in a geometric context are measured in degrees where a full circle is 360 degrees. Therefore, you could say a right angle measures 90 degrees, an acute angle is less than 90 degrees, and an obtuse angle is more than 90 degrees but less than 180 degrees.
To calculate the measure of an angle, various methods can be employed depending on the information available. For instance, if handling a triangle, the sum of the internal angles always equals 180 degrees. In cases involving circles, angles can be found by measuring the arc length or using trigonometric ratios in right triangles.