Parts & Circumference of a Circle

​Parts of a Circle

​DEFINITION: The full distance across a circle -from one side to the opposite side passing through the center

Diameter

Diameter

​DEFINITION: The distance halfway across a circle- from center to circumference (half the diameter).

Radius

Multiple Choice

Is the red line a radius or diameter of the circle?

• Radius
• Diameter

Multiple Choice

Is the red line a radius or diameter of the circle?

• Radius
• Diameter

Multiple Choice

The distance across a circle through the center is called the_______________.

• radius
• circumference
• diameter
• area

Multiple Choice

Name the part shown in the given circle.

• Radius

• Chord

• Circumference

• Diameter

Multiple Choice

The radius is twice the diameter.

• Yes it is!!!

• No it's not!!

Multiple Choice

What is the diameter?

• 8
• 16
• 10
• 4

Multiple Choice

If the radius is 4, the diameter is

• 2

• 4

• 8

• $$\pi$$

Multiple Choice

What is the radius if the diameter is 10 m ?

• 5
• 20
• 2

​Parts of a Circle

​DEFINITION: The distance all the way around the circle.

Circumference

Multiple Choice

What does "circumference" mean?

• Space a circle takes up
• Distance around a circle
• Line from one side of a circle to another
• Line from center of circle to side

Multiple Choice

What is the measurement around the outside of a circle called?

• Diameter

• Circumference

• Radius

• Center

When we are given diameter

Formulas for Circumference

When we are given radius

​DEFINITION: The number we get when we divide the circumference and the diameter.


π or 3.14 is usually used

Pi or π

Multiple Choice

Which Formula would you use?

Multiple Choice

Which Formula would you use?

Multiple Choice

Calculate the Circumference of the circle.

• 37.68 m

• 18.84

• 36

• 6

Multiple Choice

Calculate the Circumference of a Circle

• 62.8 in

• 62.4 in

• 23.14 in

• About 60 in

Multiple Choice

Calculate the Circumference of the Circle.

• 15.7 in

• 31.4 in

• 78.5 in

• 8.15 in

Multiple Choice

Calculate the Circumference of the circle.

• 18.84

• 9.42

• 27.9

• 11

Multiple Choice

Find the circumference of the circle.

• 28.26 m

• 56.52 m

• 113.04 m

• 14.13 m

Multiple Choice

Find the circumference of the circle.

• 75.36 yd

• 37.68 yd

• 18.84 yd

• 150.72 yd

Multiple Choice

Find the circumference of the circle.

• 125.6 km

• 31.4 km

• 62.8 km

• 15.7 km

Multiple Choice

What is labeled on the circle?

• Diameter

• Radius

Multiple Choice

Find the circumference of the circle.

• 15.54 cm

• 31.09 cm

• 62.17 cm

• 124.34 cm

Multiple Choice

Find the circumference of the circle.

• 18.84 cm

• 9.42 cm

• 37.68 cm

• 4.71 cm

Multiple Choice

What is labeled on the circle?

• Diameter

• Radius

Multiple Choice

Find the circumference of the circle with a diameter of 7 m. Use 3.14 for pi.

• 21.98 m

• 22.00 m

• 20.00 m

• 23.00 m

Multiple Choice

Find the circumference of the circle with a diameter of 9 in. Use 3.14 for pi.

• 28.26 in

• 25.12 in

• 30.00 in

• 31.42 in

Multiple Choice

Find the circumference of the circle with a diameter of 11 mm. Use 3.14 for pi.

• 34.54 mm

• 30.00 mm

• 36.00 mm

• 32.50 mm

Multiple Choice

Find the circumference of the circle with a diameter of 5 mi. Use 3.14 for pi.

• 15.7 mi

• 10 mi

• 20 mi

• 25 mi

Multiple Choice

What is the circumference of the circle? Round to the nearest tenth.

• 15.0 cm

• 7.9 cm

• 7.8 cm

• 15.7 cm

Multiple Choice

Find the circumference of the circle whose radius is 13 in. Round to the nearest tenth.

• 81.7 in

• 81.6 in

• 40.8 in

• 40.9 in

Multiple Choice

What is the circumference?

• 36
• 12.56
• 56.52
• 113.04

Multiple Choice

What is the circumference?

• 50.24
• 96
• 24
• 18