Circumference of any circle = 2*pi*radius or diameter*pi
Diameter = 2 * radius So in this case, 40 feet.
40'
40 ft
Area of circle: pi times radius squared
Circumference of any circle = 2*pi*radius or diameter*pi
The radius is 1/2 of the diameter, so if the radius is 20 units then the diameter is 40 units. You multiply the radius by 2 to get the diameter.
1256 inches ++ Another Answer ++ The formula for finding the Circumference of a circle is C = Pi x D where D is Diameter and Pi is 3.1416. The Radius of a circle is one-half of the Diameter, hence the Diameter of a circle with a 20-inch Radius is 40 inches. Using the formula above, multiply 40 x 3.1416 to find the Circumference: 40 x 3.1416 = 125.664 inches.
Diameter = 2 * radius So in this case, 40 feet.
40'
20 millimeters
40 ft
Area of circle: pi times radius squared
Area of a circle = πr² (remember that r or radius is exactly half of the diameter) Radius therefore = 40/2 = 20 inches Thus the Area = 3.14159 × 20 squared = 1256.636 square inches
Double the value of the radius which in this case is 2*20 = 40 feet
Twice pi multiplied by the radius will get you the result. Pi, if you are going to round to the inch, call it 3.14. The radius will be half the diameter...20 inches. Find a calculator and multiply 2 X 3.14 X 20...you can do it. You can also multiply pi times the diameter and get the same result.
In order to even discuss this question, we must assume that the unit of the '40' is the square of the unit of the '4'. -- The radius, diameter, and circumference of the circle with an area of 40 are each 10.794% shorter than the corresponding measurement in the circle with radius = 4 . -- Its area (40) is 20.423% less than the area of the circle with the radius of 4 .