Rekenmachine buitenoppervlakte

Bereken de totale buitenoppervlakte van een kubus, balk, cilinder, kegel of bol — exact in π, met elk deel apart.

Resultaat

Vul waarden in en tik op Berekenen om het resultaat te zien.

Formule

Acuboid=2(lw+lh+wh)A_{\text{cuboid}} = 2(lw + lh + wh)

Six rectangular faces, in three matching pairs.

Acylinder=2πr2+2πrhA_{\text{cylinder}} = 2\pi r^2 + 2\pi r h

Two circular ends plus the curved side.

Acone=πr2+πrl,l=r2+h2A_{\text{cone}} = \pi r^2 + \pi r l,\quad l = \sqrt{r^2 + h^2}

The base plus the curved surface, using the slant height l.

Asphere=4πr2A_{\text{sphere}} = 4\pi r^2

Four times the area of a circle with the same radius.

Zo gebruik je deze rekenmachine

  1. Choose the shape and enter its measurements in the same unit.
  2. Press Calculate. Areas come out in that unit squared.

Uitgewerkt voorbeeld

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.

Veelgestelde vragen

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).

Meer informatie