How to Calculate Area, Radius, Diameter, Circumference of Circle?

About this Tutorial:

Find How to Calculate Area, Radius, Diameter, Circumference of Circle with known single value of a circle

How to calculate, If you know a circle has an Area (A) of 19.6 square units, you can calculate Radius (r), Diameter (D), and Circumference (C) as follows:

Radius (r) = √ (A ÷ π)
Radius (r) = √ (19.6 ÷ 3.14159)
Radius (r) = √ (6.238879038957981)
Radius (r) = 2.4977737626138796

Circumference (C) = π * (r * 2)
Circumference (C) = 3.14159 * (2.4977737626138796 * 2)
Circumference (C) = 3.14159 * (4.995547525227759)
Circumference (C) = 15.6939754059142

Diameter (D) = r * 2
Diameter (D) = 2.4977737626138796 * 2
Diameter (D) = 4.995547525227759

How to calculate, If you know a circle has a Circumference (C) of 15.7, you can calculate Area (A), Diameter (D), and Radius (r) as follows:

Diameter (D) = C ÷ π
Diameter (D) = 15.7 ÷ 3.14159
Diameter (D) = 4.997465213085514

Radius (r) = D ÷ 2
Radius (r) = 4.997465213085514 ÷ 2
Radius (r) = 2.498732606542757

Area (A) =  π * r * r;
Area (A) =  3.14159 * 2.498732606542757 * 2.498732606542757
Area (A) =  7.84999336938866 * 2.498732606542757
Area (A) =  19.61505096136064 square units

How to calculate, If you know a circle has a Diameter (D) of 6, you can calculate Area (A), Circumference (C), and Radius (r) as follows:

Radius (r) = D ÷ 2
Radius (r) = 6 ÷ 2
Radius (r) = 3

Circumference (C) = π * (r * 2)
Circumference (C) = 3.14159 * (3 * 2)
Circumference (C) = 3.14159 * (6)
Circumference (C) = 18.84955592153876

Area (A) =  π * r * r;
Area (A) =  3.14159 * 3 * 3
Area (A) =  9.424769999999999 * 3
Area (A) =  28.274333882308138 square units

How to calculate, If you know a circle has a Radius (r) of 4, you can calculate Area (A), Diameter (D), and Circumference (C), as follows:

Diameter (D) = r * 2
Diameter (D) = 4 * 2
Diameter (D) = 8

Circumference (C) = π * (r * 2)
Circumference (C) = 3.14159 * (4 * 2)
Circumference (C) = 3.14159 * (8)
Circumference (C) = 25.132741228718345

Area (A) =  π * r * r;
Area (A) =  3.14159 * 4 * 4
Area (A) =  12.56636 * 4
Area (A) =  50.26548245743669 square units