A circle with a radius of 21 yards has an area of 1,385.44 square yards.
By a 21-inch circle I presume you mean that the diameter is 21 inches. So the radius is half as long, 10.5 inches. The formula for the circumference of a circle is 2 pi r, where r is the radius. Pi is about 3.14. That is accurate to 2 decimals, or 3 significant digits all together. I use that approximation because the dimension we are given has 2 significant digits. So the circumference is pi times the diameter; we multiply 3.14 by 21 inches and get 65.94. To 2 significant digits, that is 66 inches. If you meant that the radius was 21 inches, then the circumference would be twice as much, or 132 inches.
The area of a circle of radius 21 is 1386
The circumference of a circle that has a diameter of 21 is about 65.97
The area of a circle can be calculated using the formula: A = πr^2. If the diameter is 21ft, the radius would be half of that, which is 10.5ft. The area of the circle would be approximately 346 square feet.
If radius=21 ft, then diameter = 2*radius = 42 ft
21 inches.
The perimeter which is the circumference of a circle is: pi*diameter or 2*pi*radius
A circle with a radius of 21 yards has an area of 1,385.44 square yards.
By a 21-inch circle I presume you mean that the diameter is 21 inches. So the radius is half as long, 10.5 inches. The formula for the circumference of a circle is 2 pi r, where r is the radius. Pi is about 3.14. That is accurate to 2 decimals, or 3 significant digits all together. I use that approximation because the dimension we are given has 2 significant digits. So the circumference is pi times the diameter; we multiply 3.14 by 21 inches and get 65.94. To 2 significant digits, that is 66 inches. If you meant that the radius was 21 inches, then the circumference would be twice as much, or 132 inches.
The circumference of a circle is diameter times pi or pi times the radius doubled. Pi is equivalent to 22/7. Multiply 21 by 3.14 which gives you 65.999999... 7
The perimeter of a cirlcle is its circumference which is: 2*pi*radius or diameter*pi
The area of a circle of radius 21 is 1386
Its just the area of a circle 21 inches or 21 centimeters? area of a circle is (pi)*r2 where pi = 3.1415.... and r = radius thus A = (3.1415)*(diameter/2)2 u can figure out the answer from that with a calculator
The circumference of a circle that has a diameter of 21 is about 65.97
the radius is 10.5 inches. * * * * * Wrong! Circumference = 2*pi*Radius Or, Radius = Circumference/(2*pi) So circumference = 21 inches implies radius = 3.34 inches (to 3 sf)
Oh, dude, you're hitting me with the math questions? Alright, well, a 42-inch diameter circle would have a radius of 21 inches, which means the area would be pi times 21 squared, which is around 1385.44 square inches. But if you want square feet, you gotta divide that by 144 because there are 144 square inches in a square foot. So, like, the answer would be around 9.63 square feet. Math, man, it's wild.