Circles Geometry Vocabulary and Central Angles

What is the part of the circle highlighted in red called?

• semi-circle arc

• major arc

• minor arc

• sector

A ____ angle is an angle whose vertex is a the center of a circle.

• supplementary

• complimentary

• central

• obtuse

Which of the following would be a major arc in the diagram?

• BC

• BCD

• CD

• AB

Which of the following names a radius?

• segment AC

• segment DB

• segment AB

• segement BC

Find the measure of the central angle indicated. Assume that lines which appear to be diameters are actual diameters.

• x = 160
• x = 40
• x = 80
• x = 360

If the measure of arc ABC = 210°, what is the measure of ∠AOC?

• 150°

• 100°

• 210°

• 105°

What is the value of x?

• 22

• 25

• 15

• 20

Find the measure of arc AB.

• 17

• 34

• 68

• 146

Which statement is true for central angles?

• m(angle) = m(intercepted arc)

• m(angle) = ½ m(intercepted arc)

• m(angle) = ½ (big arc + little arc)

• m(angle) = ½ (big arc - little arc)