한국식 투망 규격(둘레 : circumference) 단위 : 발(150cm)

[석수]

[예시] (합사/경심) 투망(대)

크기 : 원둘레12발(약18M)
길이(Radius) : 3M
지름(Diameter) : 6M



1발은 약 150cm입니다. 옛날 성인의 평균 키 길이입니다

1발의 길이의 기준은 양팔을 벌렸을 때의 길이입니다

양팔 벌린 길이와 키는 비슷하다고 하죠!

그리고 투망의 한국식 규격은 원형으로 펼쳐졌을 때 그 둘레를 대상으로 한다


서양은 투망의 반지름 즉 투망의 꼬다리부터 납추라인까지 길이를 대상으로 한다


The perimeter of the circle can be found using either C = π × d or C = 2 × π × r.

Pi or π is a special mathematical constant, and the value of pi is approximately equal to 22/7 or 3.14. The reason that we use 3.14 is because pi is an irrational number with unlimited digits after the decimal point. The lesson about the number π will tell you more about pi. It will also shows how to derive the formula and explain why the circle's circumference is C = π × d or C = 2 × π × r.
If either the radius of a circle (r) or the diameter of a circle (d) is known, you can find the circumference by simply substituting the known value for r or d in the formula. 

The circumference is expressed in linear units.

If r or d is measured in meters, then the circumference is also measured in meters or m.

If r or d is measured in kilometers, then the circumference is measured in kilometers or km. 

If r or d is measured in inches, then the circumference is measured in inches or in.

How to find circumference of a circle using the diameter?

The product of the constant π and the diameter of the circle is equal to the circumference of the circle.

C = π × d
둘레= 3.14 × 지름


You just have to find the length of the diameter and them multiply by 3.14 to get the circumference. To get the diameter, use a ruler or a measuring tape. Measure from one edge of the circle to another edge making sure that you go through the midpoint or center of the circle (or clock). After I measured the diameter of the clock you see below, I found something close to 11.90 inches.