Up | Japanese Meaning of "Circle Ratio"  

  • 生活において，円の「大きさ」（円柱の太さ）の表現には二通りあります。
    すなわち，直径を使った表現と円周を使った表現です。
  • したがって，直径と円周の比を問題意識にもつことは，ごく自然だと言えます。

  • The ratio of the circumference to the length of diameter is called "circular ratio", and denoted by the greek letter "pi".


  • In order that this definition make sense, it is necessary that the circle ration does not depend on particular circles. And this is an implication of the fact that circles are similar one another.


  • The concept of ""

    • Circles are similar to each other.

    • In particular, the ratio of the circumference of a circle to its diameter length is constant.
      This constant is named " (pi)".


      • Especially,
          Circumference = Radius-length multiplied by (2 x )
          = Diameter-length multiplied by

      • is approximately 3.14, or 22/7.

    • Applications

      • Questions/Exercise
        • Calculate the circumference of the following circle.