How to find the circumference

2024 Author: Malcolm Clapton | [email protected]. Last modified: 2023-12-17 03:44

Choose a formula based on known quantities.

1. How to find the circumference through the diameter

Just multiply the diameter by pi.

• O is the required circumference.
• π (pi) is a constant equal to 3, 14.
• d is the diameter of the circle.

2. How to find the circumference of a circle through the radius

Multiply pi by two radii.

• O is the required circumference.
• π (pi) is a constant equal to 3, 14.
• r is the radius of the circle.

3. How to calculate the circumference in terms of the area of a circle

Multiply pi by four areas of the circle.

Find the root of the result.

• O is the required circumference.
• S is the area of the circle. Recall that a circle is a plane inside a circle.
• π (pi) is a constant equal to 3, 14.

4. How to find the length of a circle through the diagonal of the inscribed rectangle

Multiply pi by the diagonal.

• O is the required circumference.
• π (pi) is a constant equal to 3, 14.
• d - any diagonal of the rectangle.

5. How to calculate the circumference through the side of the circumscribed square

Multiply pi by the side of the square.

• O is the required circumference.
• π (pi) is a constant equal to 3, 14.
• a - any side of the square.

6. How to find the length of a circle through the sides and the area of an inscribed triangle

Multiply the sides of the triangle.

Divide the result by the area and by two.

Multiply the resulting number by pi.

• O is the required circumference.
• π (pi) is a constant equal to 3, 14.
• S is the area of the triangle.
• a, b, c - sides of the triangle.

7. How to find the length of a circle through the area and semi-perimeter of the circumscribed triangle

Divide the area of the triangle by its half-perimeter.

Multiply the result by pi and two.

• O is the required circumference.
• π (pi) is a constant equal to 3, 14.
• S is the area of the triangle.
• p - half-perimeter of a triangle (equal to half of the sum of all sides).

8. How to calculate the circumference through the side of an inscribed regular polygon

Divide 180 degrees by the number of sides of the polygon.

Find the sine of the resulting number.

Divide the side of the polygon by the result.

Multiply the resulting number by pi.

• O is the required circumference.
• a - side of a regular polygon. Recall that in a regular polygon, all sides are equal.
• π (pi) is a constant equal to 3, 14.
• N is the number of sides of the polygon. For example, if the problem has a pentagon like the image above, N would be 5.