Circle Vocabulary, Angles and Arcs

Front

What is the distance from the center of a circle to any point on its circumference called?

Back

Radius

Front

What do you call an angle whose vertex is at the center of the circle and whose sides intersect the circle?

Back

Central Angle

Front

What is the term for a part of the circumference of a circle?

Back

Arc

Front

What is the term for an arc that is less than half of the circle?

Back

Minor Arc

Front

What is the term for an arc that is more than half of the circle?

Back

Major Arc

Front

What is the term for an arc that is exactly half of the circle?

Back

Semi-Circle

Front

How many degrees are there in a full circle?

Back

360 degrees

Front

What is the longest chord in a circle called?

Back

Diameter

Front

What do you call a line that intersects a circle at two points?

Back

Secant

Front

What is the area of a sector of a circle?

Back

(θ/360) * π * r², where θ is the central angle in degrees and r is the radius.