Properties and Formulas of Circles

The video tutorial explains the concept of circumference of a circle, detailing the formulas involving radius and diameter. It introduces pi as an irrational number and its approximation. Two example problems are solved: one to find the circumference given the radius, and another to find the radius given the circumference.

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

• C = 2πr

• C = 2πd

• C = πd

• C = πr²

How is the diameter related to the radius of a circle?

• Diameter is half the radius

• Diameter is twice the radius

• Diameter is the square of the radius

• Diameter is equal to the radius

What is the approximate value of pi used in calculations?

• 3.14159

• 3.14

• 3.141

• 3.142

Which of the following is true about the number pi?

• It is a rational number

• It is exactly 3.14

• It can be written as a fraction

• It has an infinitely long decimal expansion

What is the circumference of a circle with a diameter of 10 units using π ≈ 3.14?

• 20 units

• 31.4 units

• 62.8 units

• 15.7 units

If the radius of a circle is 3 units, what is the circumference using π ≈ 3.14?

• 12.56 units

• 28.26 units

• 9.42 units

• 18.84 units

What is the circumference of a circle with a radius of 5 units using π ≈ 3.14?

• 10 units

• 25.12 units

• 15.7 units

• 31.4 units

If a circle has a circumference of 153.86 units, what is the radius using π ≈ 3.14?

• 48.5 units

• 24.5 units

• 12.25 units

• 30.5 units

What operation is used to isolate the radius when given the circumference?

• Division

• Multiplication

• Subtraction

• Addition

What is the result of dividing 153.86 by 6.28?

• 25.5

• 24.5

• 26.5

• 23.5