A circle has radius = 18

Calculate Area, Circumference, Radius, Diameter

Calculate circumference (C):

C = 2πr

C = 2π * 18

C = 36π or 113.0973

Calculate diameter (d):

d = 2r

d = 2 * 18

d = 36

Calculate Area (A):

A = πr2

A = π * 182

A = 324π or 1017.876

Final Answers


C = 36π or 113.0973
d = 36
A = 324π or 1017.876


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Common Core State Standards In This Lesson
7.G.B.4
What is the Answer?
C = 36π or 113.0973
d = 36
A = 324π or 1017.876
How does the Circles Calculator work?
Free Circles Calculator - Calculates and solves for Radius, Diameter, Circumference, and Area of a Circle.
This calculator has 1 input.
What 3 formulas are used for the Circles Calculator?
d=2r
A = 2πr2
C=2πr
What 7 concepts are covered in the Circles Calculator?
area
Number of square units covering the shape
circle
the set of all points in the plane that are a fixed distance from a fixed point
circles
circumference
the perimeter of a circle or ellips
diameter
distance from two endpoints of a circle through the center
d = 2r
origin
On a two digit coordinate plane, the point (0, 0), where the x-axis and y-axis cross.
radius
Distance from the center of a circle to the edge
C/2π
Example calculations for the Circles Calculator
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  14. Circle diameter = 5
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  29. Circle radius = 9
  30. Circle diameter = 9
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  33. Circle radius = 10
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  42. Circle diameter = 12
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  46. Circle diameter = 13
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  48. Circle circumference = 13
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  50. Circle diameter = 14
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  54. Circle diameter = 15
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  60. Circle circumference = 16
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  70. Circle diameter = 19
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  74. Circle diameter = 20
  75. Circle area = 20
  76. Circle circumference = 20
Circles Calculator Video

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