Formulas
Radius
Diameter
Circumference
Area
100
This is the formula for finding the diameter of a circle.
What is d = r x 2
100
If the diameter of the circle is 2.7mm, the Radius is this
What is 1.35mm
100
The radius of a circle is 8.2cm, the circle's diameter is this.
What is 16.4cm
100
A circle's diameter is 66cm, so its Circumference is this.
What is 207.24cm.
100
The Area of a circle is measured in this type of unit.
What is a square unit OR What are square units
200
This formula is used to find the radius of a circle.
What is r = d ÷ 2
200
If the Diameter of a circle is 8.6m, the Radius is this.
What is 4.3m
200
If the radius of a circle is 1.35km, its diameter is this
What is 2.7km
200
A circle's circumference is 375cm, so its circumference is this.
What is 375cm. (Did you think it was too easy to be true?)
200
If the radius of a circle is 15.75cm, its Area is this (Round to the nearest TENTH, please!).
What is 778.9cm^2
300
This formula is used to find the Area of a circle.
What is A = Πr2 OR What is A = Π x r x r
300
If the radius of a circle is 2.4 centimeters(cm), the radius is also THIS many millimeters (mm).
What is 24mm
300
If a circle's circumference is 31.4m, its diameter is this.
What is 10m
300
If a circle's radius is 5.25m, its circumference is this.
What is 32.97m
300
A circle's radius is 25km. Its Area is this (Round to the nearest square km please!)
What is 1 963km^2
400
This formula is used to find the Circumference of a circle.
What is C = Π x d
400
If the diameter of a circle is 16.4cm, how many MILLIMETERS is the radius?
What is 82mm.
400
If a circle's circumference is 10.9km, its diameter is this. (Round to the nearest tenth, for this one).
What is 3.5km.
400
A circle's radius is 1.35km. Its circumference is this. (This time round to the nearest HUNDREDTH)
What is 8.48km
400
A circle's Diameter is 10m. Its Area is this:
What is 78.5m^2
500
A numerical way to write Pi is this.
What is 3.14
500
If the Circumference of a circle is 8.748km, the Radius is this. (Round to the nearest tenth, just for kicks.)
What is 1.4km
500
A circle's radius is 25km, its diameter in METERS is this
What is 50 000m.
500
A circle's diameter is 16.4m. Its circumference in MILLIMETERS is this.
What is 51 496mm
500
A circle's Circumference is 18.84m. Its Area is this:
What is 28.26m^2
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