Pentagonal Pyramid Calculator

Calculator and formulas for calculating a regular pentagonal pyramid

The Pentagonal Pyramid - Golden ratio in geometric harmony!

Pentagonal Pyramid Calculator

The Regular Pentagonal Pyramid

A regular pentagonal pyramid has an equilateral pentagon as base and five congruent isosceles triangles as lateral faces.

Enter Parameters
Side length of the pentagon
Height of the pyramid
Pentagonal Pyramid Calculation Results
Slant height s:
Edge length b:
Base area A:
Slant area As:
Lateral surface AL:
Surface area S:
Perimeter P:
Volume V:
Pentagonal Pyramid Properties

The golden ratio pyramid: A pentagon as base with five triangular faces

1 Pentagon Base 5 Triangle Faces 10 Edges 6 Vertices

Pentagonal Pyramid Structure

Pentagonal Pyramid

The regular pentagonal pyramid with elegant form.
Pentagonal base with five triangular faces.

What is a regular pentagonal pyramid?

A regular pentagonal pyramid is a fascinating geometric solid:

  • Definition: Pyramid with regular pentagon as base
  • Base: Equilateral pentagon as foundation
  • Lateral faces: 5 congruent isosceles triangles
  • Vertices: 6 vertices (5 base + 1 apex)
  • Edges: 10 edges (5 base + 5 lateral)
  • Symmetry: Five-fold rotational symmetry

Geometric Properties of the Pentagonal Pyramid

The regular pentagonal pyramid shows remarkable geometric properties:

Basic Parameters
  • Faces: 6 faces (1 pentagon + 5 triangles)
  • Vertices: 6 vertices (5 base + 1 apex)
  • Edges: 10 edges (5+5)
  • Euler characteristic: V - E + F = 6 - 10 + 6 = 2
Special Properties
  • Pentagonal: Five-fold symmetry
  • Golden ratio: Pentagon relates to φ
  • Convex: All edges extend outward
  • Elegant: Harmonic proportions

Mathematical Relationships

The regular pentagonal pyramid follows elegant mathematical laws:

Volume Relationship
With π/5 factor

The volume uses the pentagonal base area. Golden ratio relationship.

Area Relationships
Trigonometry

All area formulas use π/5 angles. Pentagonal harmony.

Applications of the Pentagonal Pyramid

Regular pentagonal pyramids find applications in various fields:

Architecture & Construction
  • Special roof constructions
  • Symbolic buildings
  • Decorative tower tops
  • Modern architectural forms
Science & Technology
  • Special crystal structures
  • Optical experiments
  • Mechanical components
  • Geometric studies
Education & Teaching
  • Geometry lessons
  • Mathematical demonstrations
  • 3D modeling
  • Golden ratio studies
Art & Design
  • Sculptural forms
  • Symbolic objects
  • Product design
  • Geometric artworks

Formulas for the Regular Pentagonal Pyramid

Slant Height (s)
\[s = \sqrt{h^2 + \frac{a^2 \cdot \cot^2\left(\frac{\pi}{5}\right)}{4}} \]

Slant height with cot(π/5) ≈ 1.376

Edge Length (b)
\[b =\sqrt{s^2 + \frac{a^2}{4}}\]

Length of the pyramid edges

Base Area (A)
\[A = \frac{5 \cdot a^2}{4 \cdot \tan\left(\frac{\pi}{5}\right)} \]

Area of the regular pentagon

Slant Area (As)
\[A_s = \frac{a \cdot s}{2} \]

Area of one isosceles triangle

Lateral Surface (AL)
\[A_L = \frac{5 \cdot a \cdot s}{2} = 2.5as \]

Total area of all lateral faces

Surface Area (S)
\[S = A + A_L \]

Base area plus lateral surface

Perimeter (P)
\[P = 5 \cdot a \]

Perimeter of the pentagon

Volume (V)
\[V = \frac{A \cdot h}{3} = \frac{5a^2h}{12 \cdot \tan\left(\frac{\pi}{5}\right)} \]

One third of base area times height

Calculation Example for a Regular Pentagonal Pyramid

Given
Side length a = 8 Height h = 10 Regular Pentagonal Pyramid

Find: All properties of the pentagonal pyramid

1. Base Area Calculation

Pentagon area with tan(π/5) ≈ 0.727:

\[A = \frac{5 \cdot a^2}{4 \cdot \tan\left(\frac{\pi}{5}\right)}\] \[A = \frac{5 \cdot 64}{4 \cdot 0.727}\] \[A = \frac{320}{2.908} ≈ 110.1\]

The base area is approximately 110.1 square units

2. Slant Height Calculation

With cot(π/5) ≈ 1.376:

\[s = \sqrt{h^2 + \frac{a^2 \cdot \cot^2\left(\frac{\pi}{5}\right)}{4}}\] \[s = \sqrt{100 + \frac{64 \cdot 1.894}{4}}\] \[s = \sqrt{100 + 30.30} ≈ 11.43\]

The slant height is approximately 11.43 units

3. Volume Calculation

One third of base times height:

\[V = \frac{A \cdot h}{3}\] \[V = \frac{110.1 \cdot 10}{3}\] \[V ≈ 367.0\]

The volume is approximately 367.0 cubic units

4. The Perfect Pentagonal Pyramid
Side length a = 8.0 Height h = 10.0 Slant height s ≈ 11.43
Base area A ≈ 110.1 Volume V ≈ 367.0 ⭐ Pentagon

The regular pentagonal pyramid with golden ratio geometry

The Regular Pentagonal Pyramid: The Golden Ratio in Geometric Harmony

The regular pentagonal pyramid is an extraordinary geometric solid that combines the elegance of five-fold symmetry with the classic pyramid form. With a regular pentagon as base and five congruent isosceles triangles as lateral faces, it embodies the perfect balance between the mystical properties of the golden ratio and geometric beauty. The mathematical relationships, characterized by the trigonometric functions of the π/5 angle, make it an ideal study object for geometry and connect it directly to the golden ratio φ = (1+√5)/2 through its pentagon base.

The Geometry of Pentagonal Perfection

The regular pentagonal pyramid shows the beauty of five-fold symmetry:

  • Pentagonal Base: The regular pentagon as golden ratio foundation
  • Five-fold Symmetry: Rotational symmetry in 72° steps
  • Congruent Faces: Five identical isosceles triangles
  • Golden Ratio Connection: Pentagon relates to φ = (1+√5)/2
  • Natural Form: Relationship to pentagonal structures in nature
  • Mathematical Elegance: π/5 relationships in all formulas
  • Harmonic Proportions: Perfect balance through golden ratio

Mathematical Elegance

π/5 Trigonometry

All formulas of the pentagonal pyramid are connected by the elegant π/5 relationship, resulting from the pentagonal base and its inherent golden ratio proportions.

Golden Ratio Mathematics

The pentagonal base follows the natural laws of golden ratio geometry, which appears throughout nature in flowers, shells, and galaxies.

Structural Harmony

The five-fold symmetry and golden ratio proportions create optimal aesthetic balance, as found in classical architecture and natural forms.

Aesthetic Perfection

The harmonic proportions and natural beauty of the pentagonal pyramid make it a beloved form in art, architecture, and design.

Summary

The regular pentagonal pyramid embodies the perfect synthesis between mathematical beauty and natural harmony. Its pentagonal base and five isosceles triangular faces, described by elegant π/5 relationships and connected to the golden ratio, make it a fascinating study object of geometry. From ancient sacred geometry to modern architectural masterpieces, the pentagonal pyramid shows its timeless elegance and practical applicability. The mathematical beauty of its formulas, the natural relationship to the golden ratio, and the optimal balance between aesthetics and functionality make it one of the most fascinating geometric solids in three-dimensional geometry.