Circumference and Radius of Circles

The video tutorial covers the concept of circumference of a circle, focusing on solving problems using different formulas. It begins with an introduction to the topic, followed by detailed explanations of solving problems using the diameter and radius. The tutorial also addresses working with variables and formulas, providing examples to ensure understanding.

What is the circumference of a circle with a diameter of 9 inches using π as 3.14?

• 27.18 inches

• 25.12 inches

• 30.14 inches

• 28.26 inches

When should you use π as 22/7 instead of 3.14?

• When the area is a multiple of 7

• When the diameter is a multiple of 7

• When the circumference is a multiple of 7

• When the radius is a multiple of 7

Calculate the circumference of a circle with a radius of 7 using π as 22/7.

• 46 cm

• 40 cm

• 42 cm

• 44 cm

If only π is given, what can you assume about the diameter?

• It is 1

• It is 3

• It is 0

• It is 2

What is the radius if the diameter of a circle is 1 yard?

• 0.25 yards

• 0.5 yards

• 0.75 yards

• 1 yard

What is the formula for circumference using the radius?

• C = πd

• C = 2πr

• C = πr²

• C = 2πd

If the diameter is 3.4 inches, what is the radius?

• 1.7 inches

• 1.5 inches

• 1.6 inches

• 1.8 inches

How do you convert a diameter to a radius?

• Multiply by 2

• Divide by 2

• Add 2

• Subtract 2

What is the circumference of a circle with a radius of 1.7 inches using 2πr?

• 13.68 inches

• 12.68 inches

• 11.68 inches

• 10.68 inches

Which formula can be used to find the circumference if the diameter is known?

• C = 2πr

• C = πr²

• C = 2πd

• C = πd