Angles in Circles

π is equivalent to how many degrees?

• 180
• 90
• 360
• Mmmm... pie...

How many radians does a circle have?

• 6 radians

• 2pi radians
• pi radians
• 2 radians

A radian is the measure of an arc that is a length of its _____.

Find the arc length.  Leave your answer in terms of π.

• 7/4π
• 7/2π
• 1/8π
• 45π

The length of an arc is 18cm and the radius of the circle is 6cm. What is the radian measure of the central angle?

• 3 radian

• 2 radian

• 4 radian

• 2π radian

The diameter of a circle is 8 centimeters. A central angle of the circle intercepts an arc of 12 centimeters. What is the radian measure of the angle?

• 3

• 4

• 8π

• 3/2

What is the circumference?

• 36
• 18pi
• 108pi
• 36pi

Which angles are congruent?

• <ACB = <ADB
• <ADB=<AEB
• <AEB=<ACB
• <ACB = <ADB = <AEB

If a  quadrilateral is inscribed in a circle, then its ____angles are _____.

• adjacent; complimentary
• opposite; complimentary
• adjacent; supplementary
• opposite; supplementary

If the length of the 45° region of this circle is 10 inches, what is the radius of the circle?

• 1.6in
• 3in
• 6.8in
• 2.5in