Answer:
A circle is named by its center. The center of the given circle is A, therefore:
<u>Name of the circle:</u> A
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The radius is any line segment from the center of the circle to the perimeter.
<u>Name 4 radii:</u> ![\sf AC, \quad AB, \quad AG, \quad A\,F](https://tex.z-dn.net/?f=%5Csf%20AC%2C%20%5Cquad%20AB%2C%20%5Cquad%20AG%2C%20%5Cquad%20A%5C%2CF)
A major arc is an arc whose measure is greater than 180°.
When naming a major arc, the first point and last point are the endpoints, and we also need include the name of any point between those two endpoints.
<u>2 major arcs:</u>
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A semi-circle is half a circle with an arc that measures 180°.
Its endpoints lie on the diameter of the circle. We need three points to name a semicircle (the endpoints and a point between the endpoints).
<u>A semi-circle:</u> CEF
A minor arc is an arc whose measure is less than 180°.
<u>3 minor arcs:</u> ![\sf \widehat{FG}, \quad \widehat{GB}, \quad \widehat{BC}](https://tex.z-dn.net/?f=%5Csf%20%5Cwidehat%7BFG%7D%2C%20%5Cquad%20%5Cwidehat%7BGB%7D%2C%20%5Cquad%20%5Cwidehat%7BBC%7D)
A central angle has its vertex at the center of the circle, and is formed by 2 radii. When naming the central angle, the middle letter is the center of the circle.
<u>3 central angles:</u>
The diameter is the widest part of the circle. It is a straight line segment that passes through the center of the circle.
<u>A diameter:</u> CF
Congruent angles are angles with the same measure.
On the diagram, the same angle measures are indicated by the addition of the same number of dashes on the angle sign.
<u>Congruent angles:</u> ![\sf \angle F\,AG, \quad \angle GAB](https://tex.z-dn.net/?f=%5Csf%20%5Cangle%20F%5C%2CAG%2C%20%5Cquad%20%5Cangle%20GAB)
Adjacent arcs are arcs that have one point in common.
<u>Adjacent arcs:</u>
and
(they share point B)