Question

1. what is the degree of the angle a in the picture below?

options: 180°, 0°, 360°, 90°

Explanation:

Step1: Analyze the protractor and angle

The angle at point A is formed by two opposite rays (BA and FA), which form a straight line. A straight line forms a straight angle, and the measure of a straight angle is known to be \(180^\circ\). We can also check the protractor: the markings show that the angle spans from one end of the semicircle (0° - 180° scale) to the other, confirming it's a straight angle.

Step2: Match with options

Among the options, \(180^\circ\) corresponds to a straight angle, while \(0^\circ\) is a zero angle, \(360^\circ\) is a full circle, and \(90^\circ\) is a right angle. The angle here is a straight angle.

Answer:

\(180^\circ\) (the option with "180°")