Identifying Parts
Given Radius
Given Diameter
Given Circumference
Finding Area
100
This is a line segment with one endpoint at the center of a circle and the other endpoint on the circle.
Radius
100
Given a radius of 3 meters. Find the diameter.
3 times 2 = 6 meters
100
Given a diameter of 5 inches, find the radius.
5 divided by 2 = 2.5 inches
100
Given a circumference of 15.7 inches, find the diameter.
15.7 divided by 3.14 = 5 inches
100
Find the area of
Putting all the pieces together make a whole circle:
3.14 times 15 times times 15 = 706.5 square inches
200
This is a ratio of a circle's circumference to its diameter. In other words, circumference divided by diameter is this.
pi
200
Given a radius of 6 cm, find the circumference.
diameter = 2 times 6 = 12 cm
circumference = 3.14 times 12 = 37. 68 cm
200
Given a diameter of 4.5 cm, find the circumference.
3.14 times 4.5 = 14.13 cm
200
Given a circumference of 37.68 inches, what is the radius?
diameter = 37.68 / 3.14 = 12
radius = 12 / 2 = 6 inches
200
Find the area of the shaded region:
Rectangle = 12 times 7 = 84 square inches
Two halves make a whole
Circle = 3.14 times 3.5 times 3.5 = 38.465 square inches
Rectangle - circle = 84 - 38.465 = 45.535 square inches
300
This can found using the formula: diameter times pi.
Circumference
300
Given a radius of 4 inches, find the area.
Area = 3.14 times 4 times 4 = 50.24 square inches
300
Given a diameter of 30 inches, find the area.
radius = 30 divided by 2 = 15
area = 3.14 times 15 times 15 = 706.5 square inches
300
A wheel travels 194.68 cm. What is it's diameter?
diameter = 194.68 / 3.14 = 62 cm
300
Find the area of the shape:
Two triangles make a square: 18 times 18 = 324 square yards
Diameter of circle = 18
Radius = 18/2 = 9
Area of whole circle = 3.14 times 9 times 9 = 254. 34
Semicircle = 254.34 / 2 = 127.17
Square + Semicircle = 324 + 127.17 = 451.17 square yards
400
This is a point inside a circle that is the same distance from each point on the circle.
Center
400
A car wheel has a diameter of 20.8 inches. How far does the car wheel travel in one rotation?
One rotation = circumference
circumference = 3.14 times 20.8 = 65.3 inches
400
A bicycle wheel has a diameter of 62cm. The wheel makes 80 complete rotations. How far did it travel?
circumference = 3.14 times 62 = 194.68 cm
194.68 times 80 rotations = 15,574.4 cm
400
A car wheel has a circumference of 65.312 inches.
How far will it travel in 30 rotations?
30 times 65.312 = 1,959.36 inches
400
Find the area:
Whole Circle = 3.14 times 18 times 18 = 1,017.36
Semi-circle = 1,017.36/2 = 508.68
Quarter of a Circle = 1,017.36/4 = 254.34
Semicircle + Quarter = 508.68 + 254.34 = 763.02 square cm
500
This is a line segment that has endpoints on a circle and passes through the circle's center.
Diameter.
500
The radius of a semicircle is 9 inches. What is the area of the semicircle?
Area of Whole Circle = 3.14 times 9 times 9 = 254.34
254.34 divided by 2 = 127.17 square inches
500
Find the area in pink given the diameters.
Radius of large circle: 8/2 = 4
Area of large circle: 3.14 times 4 times 4 = 50.24
Radius of small circle: 5/2 = 2.5
Area of small circle: 3.14 times 2.5 times 2.5 = 19.625
Large area - small area = 50.24 - 19.625 = 30.615 square cm
500
The circumference of a car wheel is about 65 inches. If the car wheel rotates once per second, how far does the car travel in one minute?
1 minute = 60 seconds
65 times 60 = 3,900 inches
500
Find the area:
2 quarters make a semicircle
3.14 times 7 times 7 = 153.86 / 2 = 76.93 square cm