28.26 inches

The perimeter of the circle is called circumference of the circle. Circumference of the circle is equal to the twice of pi time radius of circle.

Circumference = 2*pi*R

Radius = Diameter/2

Radius = 9 inches/ 2

radius = 4.5 inches

Circumference = 2*pi * 4.5 inches

Circumference = 2*3.14 * 4.5 inches

Circumference = 28.26 inches

Circumference = 2*pi*R

Radius = Diameter/2

Radius = 9 inches/ 2

radius = 4.5 inches

Circumference = 2*pi * 4.5 inches

Circumference = 2*3.14 * 4.5 inches

Circumference = 28.26 inches

Circumference = PI times the diameter. Use the PI button on your calculator or try 3.14 x 9. The answer is 28.29inches square :)

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