Understanding Circumference and Pi

The video tutorial explains how to find the circumference of a circle with a given radius. It introduces the concept of Pi, a special number used in circle calculations, and explains its definition as the ratio of a circle's circumference to its diameter. The tutorial derives the formula for circumference, C = 2πr, and demonstrates how to use it to calculate the circumference of a circle with a radius of 12 inches, resulting in approximately 75.4 inches.

What is the radius of the circle mentioned in the problem?

• 16 inches

• 14 inches

• 12 inches

• 10 inches

How is Pi defined in relation to a circle?

• As the ratio of the radius to the diameter

• As the ratio of the circumference to the radius

• As the ratio of the circumference to the diameter

• As the ratio of the diameter to the circumference

Which of the following is true about the number Pi?

• It is exactly 3.14

• It is an irrational number

• It is a repeating decimal

• It is a finite number

Why is Pi considered a 'wacky' number?

• It repeats every few digits

• It is non-repeating and infinite

• It is less than 3

• It is a whole number

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

• Diameter is twice the radius

• Diameter is equal to the radius

• Diameter is half the radius

• Diameter is three times the radius

What is the formula for the circumference of a circle using the radius?

• C = 2 * r

• C = Pi * r

• C = 2 * Pi * r

• C = Pi * r^2

If the radius of a circle is 12 inches, what is the exact expression for its circumference?

• 48 * Pi

• 12 * Pi

• 24 * Pi

• 36 * Pi

What is the approximate value of Pi used in calculations?

• 3.14

• 3.14159

• 3.1416

• 3.142

How do you calculate the circumference if you know the diameter?

• Multiply the diameter by Pi

• Multiply the diameter by 2

• Multiply the diameter by 3

• Multiply the diameter by 4

What is the rounded value of the circumference to the nearest tenth?

• 75.4

• 75.5

• 75.6

• 75.3