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Pentagonal Prism Calculator

Calculate the volume, surface area, lateral area, edge, and length of a regular pentagonal prism.

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How to Calculate Pentagonal Prism Dimensions

A regular pentagonal prism is a three-dimensional solid with two parallel regular pentagonal bases and five rectangular lateral sides. It is defined by the base edge length a and the prism height/length L.

Regular Pentagonal Prism Formulas

The formulas below assume a regular pentagon base:

  • Base Area (Ab): Ab = 0.25 * √(25 + 10√5) * a² ≈ 1.720477 * a²
  • Volume (V): V = Ab * L ≈ 1.720477 * a² * L
  • Lateral Surface Area (Slat): Slat = 5 * a * L
  • Total Surface Area (S): S = 2 * Ab + Slat ≈ 3.440955 * a² + 5 * a * L
  • Apothem (incircle radius): apothem ≈ 0.688191 * a

Step-by-Step Worked Example

Calculate the properties of a pentagonal column with a base edge of 2 m and a height of 5 m:

  1. Base Area: 1.720477 * 2² = 1.720477 * 4 ≈ 6.8819 m²
  2. Volume: 6.8819 * 5 ≈ 34.41 m³
  3. Lateral Area: 5 * 2 * 5 = 50 m²
  4. Total Surface Area: 2 * 6.8819 + 50 = 13.7638 + 50 ≈ 63.764 m²

Also check: Pentagon Calculator, Hexagonal Prism Calculator, Rectangular Prism Calculator, Triangular Prism Calculator, Volume Calculator, Surface Area Calculator.

Frequently Asked Questions

How do you find the volume of a pentagonal prism?

Multiply the area of the regular pentagonal base by the prism length/height. The volume formula is: V = 1.720477 * a² * L, where a is the base edge length and L is the prism height.

What is the difference between lateral and total surface area?

Lateral surface area measures only the area of the 5 rectangular side faces: 5 * a * L. Total surface area includes the lateral area plus the area of the two pentagonal end caps: 2 * Ab + 5 * a * L.

How many faces, edges, and vertices does a pentagonal prism have?

A pentagonal prism has 7 faces (2 bases + 5 lateral sides), 15 edges (5 on each base + 5 connecting them), and 10 vertices (5 on each base).

How is the golden ratio related to a pentagonal prism?

Since the cross-section is a regular pentagon, the diagonals of its bases are related to its edge lengths by the Golden Ratio (φ ≈ 1.618034). Specifically, diagonal = a * φ.