Understanding Circles and Circumference

What is the line called that passes through the center of a circle and touches two points on its boundary?

• Radius

• Diameter

• Circumference

• Chord

Which part of a circle is defined as the distance around it?

• Radius

• Diameter

• Circumference

• Area

What is the approximate value of pi (π) used in calculating the circumference of a circle?

• 3.14

• 1.62

• 2.71

• 4.13

If the diameter of a circle is 5 cm, what is its circumference using π ≈ 3.14?

• 10.5 cm

• 12.5 cm

• 15.7 cm

• 14.7 cm

How do you calculate the circumference of a circle if the diameter is known?

• Multiply the radius by π

• Multiply the diameter by π

• Multiply the diameter by 2

• Multiply the radius by 2