Example:
What is the circumference of a circle having a diameter of 7.9 cm, to the nearest tenth of a cm? Using an approximation of 3.14159 for , and the fact that the circumference of a circle is times the diameter of the circle, the circumference of the circle is Pi × 7.9 3.14159 × 7.9 = 24.81…cm, which equals 24.8 cm when rounded to the nearest tenth of a cm.
or you could just measure it using a string and save yourself the math
to find the perimeter of a circle you simply do this (pi x D )
The formula for the perimeter of a whole circle is 2 π r therefore the perimeter of a half circle will be (2 π r)/2 which is π r n.b. the perimeter of a circle is normally referred to as the circumference...
The perimeter of a circle has the formula 2πr. Therefore the length of a semi circle is πr. But the perimeter of a semi circle also includes the diameter which is 2r. Therefore the perimeter of a semi circle = πr + 2r = r(π + 2)
by using formula 2. pie. r
There is no specific formula for a sector of a circle. There is a formula for its angle (at the centre), its perimeter, its area.
perimeter = circumference
this is called finding the circumference. The formula is 2*pie*radius
The formula for the circumference of a circle is pi * diameter or (2 radius.)
The circumference of a circle is the length of the circle's perimeter.
Circumference ("perimeter") of a circle = (pi) x (diameter of the circle)
The perimeter is equal to Pi times the diameter.
To find the circumference (distance around) of a circle, use the formula pi x d (d=diameter)