Formulas
Parts of a circle
Circumference
Area
Random Circle
100
What is the formula to find the diameter if the radius is given?
D = 2r OR D= 2(r)
100
What is the green line?
Radius
100
What is the circumference when the diameter is 8m?
25.12cm
100
what is the formula for the Area of a circle?
A = pir^2
100
Do we need to find circumference or area?
Question: Find the distance around a Ferris wheel.
circumference
200
What is the formula for circumference of a circle?
c =
pi d
2 pi r
200
What is the Orange line?
Diameter
200
What is the circumference of a circle with a radius of 4 ft?
25.12 ft
200
What is the area of a circle with Radius 1 cm
3.14 cm2
200
Approximately how long is the circumference of a circle compared to its diameter?
approximately 3.14
300
What is the formula for the area of a circle?
a =
pi r^2
300
What is the Blue line?
Circumference
300
What is the circumference? 
C = 125.6 in
300
Find the area
A = 113.04 cm2
300
💡💡**DAILY DOUBLE**💡💡
Do we need to find Area or Circumference:
Question: Find the amount of oil it takes to cover the bottom of a frying pan.
Area!
400
What is the formula for the Area of a Rectangle?
A= L x W
400
What is the Grey part showing?
Area
400
What is the diameter when the circumference is
18 cm? Round to the nearest hundredths.
5.73 cm
400
Find the area of a circle when the diameter is 14 cm?
153.86 cm2
400
What is the total degrees of any circles?
A circle consists of 360 degrees.
500
Write a formula for the area of a square?
A= s2 OR A= S x S
500
Which line segment(s) shows radius? Is it line from B to D? A to F? H to A? H to F? D or G? Choose two from the choices.
line HA and line AF
500
What is the area of a circle with a diameter of 10 m?
78.5 m2
500
What is the area of the circle when the radius is 2cm?
12.56 cm2
500
Find the decimal number that represents this diagram:
0.3 (repeating)