Parts of a Circle

Define "radius"

• The measurement from the center of a circle to an edge of the circle.

• The measurement around the circle

• The measurement from and edge of the circle to another edge through the center

• A line perpendicular to the diameter of the circle

What is the mathematical name given for the line OA?

• Diameter

• Radius

• Tangent

• Chord

What is being represented in the image?

• Radius

• Diameter

• Inscribed Angle

• Secant

What is the distance around a circle?

• Circumference
• Area
• Diameter
• Radius

If my radius is 10ft, what is my diameter?

• 20ft
• 5ft
• 31.4ft
• 62.8ft

Find the radius of a circle who's diameter is 40 ft.

• 40ft

• 80ft

• 20ft

• 45ft

Match the following:

• The distance around a circle. Perimeter of a circle.

• Circumference (C)

• The distance from one side of a circle to the other. Cuts a circle in half.

• diameter (d)

• The number of diameter lengths it takes to make a circumference of a circle.

• radius (r)

• Half the diameter.

• π

What is the measurement around the outside of a circle called?

• Diameter

• Circumference

• Radius

• Center

Choose the answer which best describes how these formulas are related to each other.

• They both solve for circumference. In the first formula it uses diameter, in the second formula it uses two times the radius, which is the same thing as diameter.

• They both solve for circumference, in the first uses diameter and the second uses pi.

• They both solve for area. In the first formula it uses diameter, in the second formula it uses two times the radius, which is the same thing as diameter.

• They both use circumference to solve for pi. One uses radius, the other uses diameter.

Which Formula would you use?

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