Circles and Circumference

What is the formula to calculate the circumference of a circle?

• 3 * π * r

• 2 * π * r

• π * r^2

• 2 * π * r^2

If the radius of a circle is 5 cm, what is its circumference? (Use π = 3.14)

• 15.7 cm

• 31.4 cm

• 10 cm

• 25 cm

What is the diameter of a circle?

• Half the radius of the circle

• The area of the circle

• The circumference of the circle

• Twice the radius of the circle

What is the relationship between the radius and the diameter of a circle?

• The diameter is twice the length of the radius.

• The diameter is half the length of the radius.

• The radius is twice the length of the diameter.

• The radius and diameter are equal in length.

What is the formula to calculate the area of a circle?

• π/r

• 2πr

• r/2

• πr^2

What is the name of the line segment that passes through the center of a circle and has its endpoints on the circle?

• tangent

• chord

• diameter

• radius

What is the name of the point inside a circle that is the same distance from every point on the circle?

• edge

• corner

• center

• perimeter

What is the ratio of the circumference of a circle to its diameter?

• 4

• 2

• 3

• π

What is the name of the line segment that connects two points on the circle?

• Radius

• Tangent

• Diameter

• Chord

If the circumference of a circle is 31.4 cm, what is its radius? (Use π = 3.14)

• 5

• 10

• 20

• 15