表面積の計算機
立方体、直方体、円柱、円錐、球の表面積を、π を使って正確に、各部分を示しながら求めます。
結果
値を入力して「計算」を押すと結果が表示されます。
公式
Six rectangular faces, in three matching pairs.
Two circular ends plus the curved side.
The base plus the curved surface, using the slant height l.
Four times the area of a circle with the same radius.
この計算ツールの使い方
- Choose the shape and enter its measurements in the same unit.
- Press Calculate. Areas come out in that unit squared.
解き方付き例題
A cylinder with radius 3 and height 5
The two circular ends: 2π × 3² = 18π.
The curved side: 2π × 3 × 5 = 30π.
Total surface area = 18π + 30π = 48π ≈ 150.796447.
よくある質問
What is the difference between surface area and volume?
Surface area is the area of the outside (how much paint covers it); volume is the space inside (how much it holds).
What is the slant height of a cone?
The distance from the tip down the side to the edge of the base: l = √(r² + h²).