A half turn is 180° and is known as a straight angle (or angle on a straight line). A three-quarter turn is 270°. An acute angle is less than 90°. An obtuse angle is between 90° and 180°.
The following is a summary of “Investigation of the Relationship Between the Measured Alpha Angle in Capnography and Readmission Within Thirty Days in Chronic Obstructive Pulmonary Disease Patients ...