When you multiply 12.8 times pi the exact answer is12.8 Pi, but you can round off the answer to40.192because pi is about equal to 3.14.
pi times radius or diameter equals are of a cirlce
The circumference is 56.55 cm
Circumference is 2 times pi times radius, so the circumference of this circle is 2 times pi times 5, or 10 times pi. If a decimal answer is needed, pi is approximately 3.14, so C=31.4
The area is 9 feet. You find the square root of 81 which is 9. I want circumference, not area.
The radius is 9 feet because pi*92 = 81*pi
3.141592653589793 * 81 = 254.469
(pi) R2 x 34 = 81 pi R2
In every circle . . .Area = (pi) x (radius)2Diameter = 2 x radiusCircumference = (pi) x diameterIn this circle, Area = (pi) R2 = 81R2 = 81/piR = sqrt( 81/pi )Diameter = 2 x sqrt( 81/pi )Circumference = (pi) x 2 x sqrt( 81/pi ) = 2 x sqrt( 81 pi ) = 18 sqrt(pi) = 31.9042 (rounded)
Area of circle: 81*pi square units
3.14 x 81 = 254.34
Divide the 81 pi by pi, then square root it. (Use the formula for area of circle, which gives 81pi=pi*radius squared, but rearrange to find the radius). i.e. it's the square root of 81
If: pi*radius2 = 81*pi sq ft Then: radius = 9 feet Circumference = 2*pi*9 = 56.549 feet rounded to 3 decimal places
How about: 9 times 9 = 81 or 81 times 1 = 81
The Egyptians used 256 divided with 81 to calculate pi.
648pi. (pi = 3.14159...)Area of a circle = (pi) x (radius squared)= (pi)(9 squared) = (pi)81.Area of a cylinder = area of circle x height.= (pi)81 x 8= 648(pi)
81 times 7 or 7 times 81 equals 567