Understanding Circumference of Circles

The video tutorial explains the concept of circumference, which is the distance around a circle. It introduces the formula for calculating circumference using the diameter, which is circumference = pi x diameter, where pi is approximately 3.14. An example is provided using a circle with a diameter of 20 centimeters, resulting in a circumference of 62.8 centimeters. The tutorial also covers how to calculate circumference using the radius with the formula circumference = 2 x pi x radius, demonstrated with a cake having a radius of 6 centimeters, resulting in a circumference of 37.68 centimeters.

What is the circumference of a circle?

• The distance across the circle

• The distance around the circle

• The area of the circle

• The radius of the circle

Which formula is used to calculate the circumference of a circle using its diameter?

• Circumference = 2 x pi x radius

• Circumference = pi x radius

• Circumference = diameter / pi

• Circumference = pi x diameter

What is the approximate value of pi?

• 2.71

• 4.13

• 3.14

• 1.62

If the diameter of a circle is 20 cm, what is its circumference using pi as 3.14?

• 62.8 cm

• 31.4 cm

• 125.6 cm

• 94.2 cm

How do you calculate the circumference of a circle if you only know the radius?

• Circumference = 2 x pi x radius

• Circumference = radius / pi

• Circumference = pi x diameter

• Circumference = 2 x diameter