lesson 2 mi/vocab circle center diameter circumference radius estimate and find the circumference of...
TRANSCRIPT
• circle
• center
• diameter
• circumference
• radius
• Estimate and find the circumference of circles.
Find the Radius
The diameter of a circle is 48 centimeters. Find the radius.
Answer: The radius is 24 centimeters.
A. A
B. B
C. C
D. D
A. 2 m
B. 8 m
C. 16 m
D. 32 m
The diameter of a circle is 16 meters. Find the radius.
Find the Diameter
The radius of a circle is 9 inches. Find the diameter.
Answer: The diameter is 18 inches.
1. A
2. B
3. C
4. D
A. 11 cm
B. 22 cm
C. 44 cm
D. 88 cm
The radius of a circle is 22 centimeters. Find the diameter.
Estimate the Circumference
Estimate the circumference of the circle.
Answer: The circumference is about 18 meters.
Replace π with 3 and d with 6.
C = πd
1. A
2. B
3. C
4. D
A. 6 yd
B. 8 yd
C. 12 yd
D. 16 yd
Estimate the circumference of the circle.
Estimate the circumference of the circle.
Answer: The circumference is about 90 millimeters.
Estimate the Circumference
Replace π with 3 and r with 15.
C = 2πr
A. A
B. B
C. C
D. D
A. 8 in.
B. 12 in.
C. 24 in.
D. 72 in.
Estimate the circumference of the circle.
A. A
B. B
C. C
D. D
A. 36 cm
B. 15 cm
C. 37 cm
D. 72 cm
Estimate the circumference of the circle.
PETS Find the circumference around the hamster’s running wheel. Round to the nearest tenth.
Answer: The distance around the hamster’s running wheel is about 18 inches.
Find Circumference
C = 2r
A Divide the diameter by π.
B Multiply the radius by π.
C Multiply the diameter by 2, and then multiply by π.
D Multiply the diameter by π.
Choose the Correct Method
BASKETBALL Anna knows the diameter of a basketball hoop but would like to find the circumference. Which method can she use to find the circumference of the basketball hoop?
Read the Test Item You need to find the circumference of the basketball hoop. You know the diameter of the basketball hoop.
Answer: D
A. A
B. B
C. C
D. D
A standard baseball has a circumference of 9 inches. Which method can be used to find the radius of the baseball?
A. Divide the circumference by π and then multiply by 2.
B. Divide the circumference by π and then divide by 2.
C. Multiply the circumference by π and then multiply by 2.
D. Multiply the circumference by π and then divide by 2.
Malik`s bike tire has a radius of 8 inches. Which equation could be used to find the circumference of the tire in inches?
8 .
16 .
2 16 .
4 A.
CD
CC
CB
C
The distance around a tree trunk is the girth of the tree. Which measure is closest to the girth of the cross-section of the tree shown below?
A. 33 in.
B. 66 in.
C. 138 in.
D. 380 in.