Understanding Circles and Pi

What is a circle defined as in geometry?

• A shape with four equal sides.

• A set of all points that are equidistant from a single point.

• A shape with three angles.

• A line that goes on forever in one direction.

What is the central point of a circle called?

• The edge

• The perimeter

• The center

• The diameter

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

• Diameter

• Circumference

• Radius

• Arc

What is the distance across a circle, passing straight through its center, called?

• Radius

• Circumference

• Diameter

• Chord

How does the diameter of a circle relate to its radius?

• The diameter is half the radius.

• The diameter is three times the radius.

• The diameter is twice the radius.

• The diameter is unrelated to the radius.

What is the special name for the perimeter of a circle?

• Area

• Circumference

• Diameter

• Radius

What is the Greek letter used as the symbol for the mathematical constant Pi?

• Alpha (α)

• Beta (β)

• Gamma (γ)

• Pi (π)

Pi (π) represents the ratio of which two measurements of a circle?

• Radius to diameter

• Area to radius

• Circumference to diameter

• Diameter to circumference

What is the approximate value of Pi (π) often used in calculations?

• 2.71

• 3.00

• 3.14

• 4.00

What characteristic defines an irrational number like Pi?

• Its decimal digits end after a few places.

• Its decimal digits repeat in a pattern.

• Its decimal digits never end and never repeat.

• It can always be written as a simple fraction.