Formulas
What are both formulas for Circumference of a circle?
C=πd
C=2πr
A circle has a radius of 2, what is the diameter?
4
What is the circumference of a circle with a diameter of 10? (In terms of π)
C=10π
What is the area of a circle with a radius of 3 feet? (in terms of π) (Include your units)
A = 9π feet2
Pi day falls on this day every year.
March 14th aka 3.14
Diameter is ________ the radius.
Twice
d=2r
A circle has a diameter of 12, what is the radius?
6
What is the circumference of a circle with a radius of 7? (In terms of π)
C=14π
What is the area of a circle with a diameter of 10 centimeters? (in terms of π) (Include your units)
A = 25π centimeters2
Is pi a rational or irrational number?
Irrational
Radius is _______ the diameter.
half
r = d/2
The diameter is 17.5, what is the radius?
8.75
What is the circumference of a circle with a diameter of 15 inches ? (Use 3.14 for π) (Include your units)
C = 47.1 inches
What is the area of a circle with a radius of 4 inches? (Use 3.14 for π) (Include your units)
A=50.24 inches2
What are the first 8 digits of pi?
3.1415926
Circumference is the _______________ around a circle.
distance
The radius of a circle is 34 inches, what is the diameter? (Include your units in your answer or its wrong)
68 inches
What is the circumference of a circle with a radius of 17.5 centimeters? (Use 3.14 for π) (Include your units)
C = 109.9 centimeters
What is the area of a circle with a diameter of 15 centimeters? (Use 3.14 for π) (Include your units)
A = 176.625 centimeters2
Pi Day, 2015 9:26am/pm is special for this reason
The first 8 digits of pi correspond to the date and time. It only happens once every 100 years. (3.1415926 = March 14, 2015 9:26)
What is the formula for area of a circle?
A=πr2
The diameter of a circle is 42 centimeters, what is the radius? (Include your units)
21 centimeters
If the circumference of a circle is 34.54 feet, what is the diameter? (Read it again, think about what you know, include your units)
d = 11 feet
A circle has a diameter of 26 units. What is the area of the circle to the nearest hundredth of a square unit?
530.66
Pi is approximately 3.14 but as a fraction pi is
22/7