How many degrees are in a straight angle?

• A. 90°
• B. 180°
• C. 360°
• D. 270°

Answer: (B)

A straight angle measures exactly 180 degrees. This is defined as the angle that forms a straight line, dividing the line into two equal halves. In geometric terms, when two rays emanate from a common point and create an angle of 180 degrees, they point in exactly opposite directions, establishing a linear arrangement.

To visualize this, imagine drawing a straight line: if you were to denote an angle formed by points on either end of this line (with the vertex being the midpoint), the complete rotation from one end of the line to the other would encompass 180 degrees.

The other options represent various types of angles: for instance, a right angle is 90 degrees, a full rotation — or complete angle — is 360 degrees, and an obtuse angle can be any angle greater than 90 degrees but less than 180 degrees, which is typically not used to describe a straight angle.