To determine the measure of a major arc, let's first understand what an arc in a circle is and how it is categorized.
1. Arc of a Circle:
- An arc of a circle is a portion of the circumference of the circle.
2. Semicircle:
- A semicircle is an arc that represents half of the circle. Because a full circle measures 360 degrees, a semicircle measures exactly 180 degrees.
3. Categorization of Arcs:
- Arcs can be categorized into minor arcs, semicircles, and major arcs.
- Minor Arc: An arc that is less than 180 degrees.
- Semicircle: An arc that is exactly 180 degrees.
- Major Arc: An arc that is greater than 180 degrees.
Since the question specifically asks about a major arc, it is important to focus on this categorization:
4. Measure of a Major Arc:
- By definition, a major arc must measure more than a semicircle.
- Since a semicircle measures 180 degrees, a major arc must be any arc that measures more than 180 degrees.
Therefore, when asked about the measure of a major arc, it is determined that the measure is:
- Greater than 180 degrees.
So, the correct answer is:
C. greater than 180°.
