this depends on which penny you are asking about.
The US penny, the Australian penny, the British penny, Canadian penny and the Irish penny coin.
Each one is a different size and weight.
Diameter of an Australian penny (no longer currency) is 1 and 3/16".
Diameter of an old British penny (no longer in use) was 1.25". Modern pennies are 20.03 mm, or about 4/5"
Diameter of a U.S. cent (penny) - 0.75"
Diameter of an Australian penny (no longer currency) is 1 and 3/16".
0.75"
Well, honey, a penny has a diameter of about 0.75 inches, so we can calculate the surface area using the formula for the area of a circle. The surface area of a penny is approximately 0.441 square inches. So, there you have it, the glamorous surface area of a humble little penny.
Circumference: 0.75 times pi = 2.356 inches rounded to three decimal places
The US one-cent coin is 0.750 inches in diameter and 0.061 inches thick,for a volume of 0.027 cubic inches.The UK plated-steel penny (one new pence) is 20.32 mm in diameter and 1.65 mm thick, for a volume of 0.535 cm3 or about 0.033 cubic inches.(see related question)
Diameter of an Australian penny (no longer currency) is 1 and 3/16".
0.75"
The size of the penny is very important. The weight of it is 2.500 grams exactly. The diameter is 0.750 inches or 19.05 mm or 1.905 centimeters.
A PENNY coin has a Diameter of exactly 1&3/16ths Inches which is same as 1.1875 inch. The foregoing applies to a British penny. A US 1 cent piece is 19.05mm (.75 inches) in diameter, 1.55mm thick, and weighs 2.5 grams
.75 inches or 19 Millimeters is the diameter so the radius is .375 inches or 9.5 Millimeters.
Circumference: 0.75 times pi = 2.356 inches rounded to three decimal places
Well, honey, a penny has a diameter of about 0.75 inches, so we can calculate the surface area using the formula for the area of a circle. The surface area of a penny is approximately 0.441 square inches. So, there you have it, the glamorous surface area of a humble little penny.
The US one-cent coin is 0.750 inches in diameter and 0.061 inches thick,for a volume of 0.027 cubic inches.The UK plated-steel penny (one new pence) is 20.32 mm in diameter and 1.65 mm thick, for a volume of 0.535 cm3 or about 0.033 cubic inches.(see related question)
The diameter of a penny is 0.750-inches. A United States penny is made of copper-plated zinc. Coins that are worn, but still recognizable and coins that are chipped or mutilated are melted and reused.
The diameter of a US penny is 0.01905 metres
The inches in a diameter = 2 X inches in the radius. Or, inches in a diameter = inches in circumference / pi
What is a "8 inch ball" ? Is 8 inches the diameter ? Then its diameter is 8 inches. Is 8 inches the radius ? Then its diameter is 16 inches. Is 8 inches the circumference ? Then its diameter is about 2.546 inches (rounded).