Exploring Circles and Their Circumference

What tool is recommended to use during this lesson on circles?

• Ruler

• Calculator

• Protractor

• Compass

If the diameter of a circle is 20 feet, what is the radius?

• 20 feet

• 10 feet

• 5 feet

• 40 feet

When given the radius, how do you find the diameter?

• Multiply the radius by 2

• Subtract pi from the radius

• Add pi to the radius

• Divide the radius by 2

Which formula can be used to calculate the circumference of a circle?

• C = pi * radius

• C = 2 * pi * radius

• C = pi * diameter

• C = 2 * pi * diameter

What is the circumference of a circle if the radius is 5 inches and pi is approximated as 3.14?

• 62.8 inches

• 15.7 inches

• 10.45 inches

• 31.4 inches

What is the correct circumference for a circle with a diameter of 14 feet using pi as 3.14?

• 22 feet

• 87.92 feet

• 43.96 feet

• 28 feet

How do you find the circumference of a semi-circle with a diameter of 6 using pi as 3.14?

• 15.42

• 12.56

• 18.84

• 9.42

What additional step is required when calculating the perimeter of a semi-circle?

• Add the radius

• Divide by two

• Multiply by two

• Add the diameter

What is the first step in calculating the circumference of a semi-circle?

• Add the diameter

• Divide by two

• Calculate full circle circumference

• Subtract the radius

If the circumference of a circle is 75 and pi is 3.14, what is the diameter?

• 47.77

• 150

• 37.58

• 23.88