Circumference definition and formula
Find the circumference is the circumference or the distance around it. Expressed as C in the formula, it has units of distance such as millimeters (mm), centimeters (cm), meters (m), and inches (in). It is related to the radius, diameter, and pi using the following equations:
C = πdC
Where d is the diameter of the circle, r is its radius, and π is the pi. The diameter of a circle is the longest distance across the circle and can be measured from any point on the circle through the center or origin of the circle to the opposite connection point.
The radius is half the diameter or can be measured from the origin of the circle to its end.
π (pi) is a mathematical constant that associates the circumference of a circle with its diameter. There is no decimal representation because this is an irrational number. In calculations, most people use 3.14 or 3.14159. It may be approximated by a fraction of 22 / 7.
Find the circumference-example
- Measure the diameter of the circle as 8.5 cm. Find the circumference.
Don’t forget to report your answer in the appropriate units. To solve this, just enter the diameter in the equation.
C = πd C =
3.14 * (8.5 cm)
C = 26.69 cm, which should be rounded up to 26.7 cm
2. I want to know the circumference of a pot with a radius of 4.5 inches.
For this problem, you can either use an expression that includes the radius or remember that the diameter is twice the radius and use that expression. The solution using the radius formula is:
C = 2πr C =
2 * 3.14 * (4.5
inches ) C = 28.26 inches or 28 inches (if using the same significant digits as the reading ) .
3. If you measure the can, you can see that the circumference is 12 inches. What is its diameter? What is its radius?
A can is a cylinder, but since a cylinder is basically a stack of circles, it has a circumference. To solve this problem, we need to reorder the equations.
C = πd can be rewritten as follows
. C / π = d
Insert the value of the circumference and solve d.
C / π = d
(12 inches) / π = d
12 / 3.14 = d
3.82 inches = diameter (let’s call it 3.8 inches)
You can play the same game and rearrange the formula to solve the radius, but if you already have a diameter, the easiest way to get the radius is to split the radius in half.
Radius = 1/2 * Diameter
Radius = (0.5) * (3.82 inches) [Remember, 1/2 = 0.5]
Radius = 1.9 inches
Notes on reporting quotes and answers
You should always check your work. One easy way to estimate whether the circumference’s answer is valid is to see if the circumference is just over 3 times the diameter or just over 6 times the radius.
If you don’t know what the significant digits are, or if you’re not asked to work with them, don’t worry about The number of significant digits used for pi must match the number of significant digits of the other given values. This. Basically, this means that if you have a very accurate distance measurement like 1244.56 meters (6 significant digits), use 3.14159 for pi instead of 3.14. Otherwise, you will report an inaccurate answer.
Find the area of a circle
If you know the circumference, radius, or diameter of a circle, you can also find its area. The area represents the space surrounded by a circle. As such a CM, give in units of squared distance 2 or M 2.
The area of a circle is given by the following equation.
A = πR 2 (equal to area radius squared PI times.)
A = π (1/2 d) 2 (Area is equal to pi multiplied by half the square of the diameter.)
A = π (C / 2π) 2 (The area is equal to the pi of pi divided by twice the pi)