Circumference

Circumference

What is "circumference"?

What is PERIMETER and how is it found?

PERIMETER is the distance around an object.

Perimeter is found by adding all of the sides of a figure together.

Distance is measured in many different types of units.

Multiple Choice

Which of the following units does NOT measure DISTANCE?

• feet

• inches

• degrees

• yards

What is CIRCUMFERENCE and how is it found?

CIRCUMFERENCE is the perimeter of (distance around) a circle.

Since circles don't have "sides", a different method must be used to find the distance around a circle.

CIRCUMFERENCE can by found two ways

When do you use the circumference formula and which one do you use?

Multiple Choice

What is the circumference of a circle whose radius is 4 inches?

• C = 4 inches

• C = 8 $$\pi$$

• C = 4 $$\pi$$

• C = 2 $$\pi$$

Multiple Choice

What is the circumference of a circle whose diameter is 10 feet?

• C = 10 feet

• $$C\ =\ 10\pi$$ feet

• $$C\ =\ 5\pi$$ feet

• $$C\ =\ 20\pi$$ feet

Multiple Choice

If a circle's circumference is  $$14\pi$$  yards, what is the radius?

• r = 14 yards

• r = 7 degrees

• r = 28 yards

• r = 7 yards

Multiple Choice

If a circle's circumference is  $$24\pi$$  miles, then what is the diameter?

• d = 12 miles

• d = 24 miles

• d = 12 degrees

• d = 24 degrees

What is ARCLENGTH?

ARCLENGTH is the LENGTH of an ARC.

Arclength, like circumference, is a distance.

Distance is measured in units like centimeters, meters, yards, feet, miles.....NOT degrees.

DEGREES IS NOT A MEASUREMENT OF DISTANCE!!!

What is the formula for finding the length of an arc?

Multiple Choice

What is the length of an arc that measures $$180\degree$$ if the radius is 6 meters?

• arclength = $$180\degree$$

• arclength = 6 meters

• arclength = $$6\pi$$ meters

• arclength = $$12\pi$$ meters

When is the formula for arc length used?

The formula for arc length is used when finding an arc's length (of course) as well as when an arc's length is GIVEN (and a radius, diameter or circumference is needing to be found).