Finding Circumference Given Diameter/Radius II 4/29/15 Page 133
3. A bagel shop has a circular bagel sign in its
parking lot with a radius of 4 feet. The shop
owner is putting a string light on the outline of
the sign. How much lighting is needed? The
owner needs ____________ feet of lighting.
Do Now: The circumference or distance around this
circle is ___________ inches.
Formula:
Formula:
4. The circular lid of a barrel has a diameter of 62
centimeters. The circumference or distance
around this lid is ___________ centimeters.
Formula:
Which formula do I use?
𝐶 = 𝜋𝑑 or 𝐶 = 2𝜋𝑟
1. The circumference or distance around this circle
is ___________ mm.
5. The radius of a cup is 7 centimeters. Mr. Jow
wants to find the circumference or distance
around the cup so he multiplies (7) 𝜋. Explain
his error.
Formula:
Formula:
Homework Use 3.14 for π unless otherwise told.
2. The shape of a snare drum head is a circle. The
diameter of the drum head is 14 inches. The
circumference or distance around this snare
drum head is ___________ inches.
Formula:
1.
A.
B.
C.
D.
The diameter of the circular top of an oatmeal
container is 10 centimeters. Which of the following
expressions can be used to determine the
circumference of the top of the oatmeal container in
centimeters?
10  
20 x 
20  
10 x 
2.
The diameter of a circular plate is approximately 6
inches. Find the circumference of the plate. Show
work.
 x 6 = 18.84 in
3.

The diameter of a wheel is 5 inches. If the wheel rolls
4 times, what is the distance it traveled?
11. A circular puzzle has a radius of about 50 inches.
Which expression can be used to find the
approximate circumference of this puzzle?
x 5 x 4 = 62.8 inches
50  
50  (2  )
50 x (2  )
50 x 
A.
B.
C.
D.
For questions, 4-8, TRUE OR FALSE
4.
The length of the diameter of a circle is ½ the length
of the radius of the circle.
12. The radius of a wheel is 4 inches. If the wheel rolls 5
times, what is the distance it traveled?
FALSE
5.
The length of the radius of a circle is twice the length
of the diameter of the circle.
2X
FALSE
6.

X 4 X 5 = 125.6 inches
The ratio of the circumference to the diameter of a
circle is approximately 3 to 1.
TRUE
7.
Is the circumference about 3 times larger than the
diameter?
13. The length of the radius is half the length of the
diameter.
TRUE
8.
1
Is the diameter about the length of the
3
circumference?
TRUE
9.
For questions, 13-14, TRUE OR FALSE
Find the following properties:
TRUE
14. The circumference is about 6 times longer than the
radius.
TRUE
Diameter = 8 cm
Radius = ___4_____ cm
15. Find the following
properties:
Circumference = 25.12 cm
Diameter = ___6_____ cm
Radius = 3 cm
Circumference = _18.84_______ cm
10. Josue sliced an orange into circular pieces to put into
a bowl of punch. The radius is 4 centimeters. Which
expression can be used to find the approximate
circumference of this piece of orange?
A. 2(4)
B.  (4)
C. 2(  )(8)
D. 2(  )(4)