Circle Basics Review

If you know the diameter, how do you calculate the radius?

• Add 2

• Subtract 2

• Multiply by 2

• Divide by 2

Which is the formula for circumference?

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Find the diameter 
C=12π

• 12

• 24

• 6

• 144

Find the radius 
C=6π

• 6

• 3

• 36

• 18.8

A ball has a circumference of 9.42 cm. What is the diameter?

• 29.5788 cm

• 59.1576 cm

• 3 cm

• 1.5 cm

Find the EXACT area of the circle.

Find the EXACT area of the circle.

An angle whose vertex is the center of a circle is a(n) ______.

• inscribed angle

• acute angle

• obtuse angle

• central angle

An angle whose vertex is on a circle and whose sides contains chords of the circle is _______

• an inscribed angle

• a central angle

• an obtuse angle

• a semicircle

Find the red minor arc and its measure. Then find the blue major arc and its measure.

• AB, 135; ADB, 225

• ADB, 225; AB, 135