A regular icosahedron is a solid with 20 identical equilateral-triangle faces — another of the five Platonic solids, and the shape behind many 20-sided dice and geodesic dome designs.
A regular icosahedron is a solid with 20 identical equilateral-triangle faces — another of the five Platonic solids, and the shape behind many 20-sided dice and geodesic dome designs. This calculator finds the volume and surface area from a single edge length.
A 20-sided die (d20) has an edge length of 1 cm. Volume = (5(3+√5)/12) × 1³ ≈ 2.18 cm³. Surface Area = 5√3 × 1² ≈ 8.66 cm².
It's a 3D shape with 20 equilateral triangular faces, 12 vertices, and 30 edges — one of the five Platonic solids.
Volume = (5(3+√5))/12 × edge length³, derived from its regular triangular-faced geometry.
A 20-sided die (d20) used in tabletop gaming is a classic icosahedron, and the shape appears in some virus capsid structures in biology.