There are two objects, one convex and one nonconvex, that can both be called regular icosahedra. Each has 30 edges and 20 equilateral triangle faces with five meeting at each of its twelve vertices. Both have icosahedral symmetry.

12

Furthermore, what shape is a d20? icosahedron

Correspondingly, what do you call a 20 sided die?

The shape of a typical **20**–**sided die** is what’s mathematically **called** an icosahedron.

How many sides does a octahedron have?

Other convex octahedra More generally, an octahedron can be any polyhedron with eight faces. The regular octahedron has 6 vertices and **12** edges, the minimum for an octahedron; irregular octahedra may have as many as **12** vertices and 18 edges.

### What is a 12 sided shape called?

In geometry, a dodecagon or 12-gon is any twelve-sided polygon.

### What is a 100 sided shape called?

Polygons are named after the number of sides that they have. A 100-sided polygon is called a hectogon. Take the hundreds digit, find it on the column for ones digits, then stick a “hecta” to its right. Now number off the tens and ones like above: (hundreds)hecta(tens)kai(ones)gon .

### What is a shape with 10000 sides?

In geometry, a myriagon or 10000-gon is a polygon with 10,000 sides.

### What is a icosahedron used for?

Icosahedral dice with twenty sides have been used since ancient times. In several roleplaying games, such as Dungeons & Dragons, the twenty-sided die (d20 for short) is commonly used in determining success or failure of an action. This die is in the form of a regular icosahedron.

### What is a 13 sided 3d shape called?

In geometry, a tridecagon or triskaidecagon or 13-gon is a thirteen-sided polygon.

### What is a 10 sided shape called?

In geometry, a decagon is a ten-sided polygon or 10-gon.

### Why is it called a dodecahedron?

It is called a dodecahedron because it is a polyhedron that has 12 faces (from Greek dodeca- meaning 12).

### Why are there only 5 Platonic solids?

The Greeks recognized that there are only five platonic solids. But why is this so? The key observation is that the interior angles of the polygons meeting at a vertex of a polyhedron add to less than 360 degrees.

### What is a 11 sided shape called?

In geometry, a hendecagon (also undecagon or endecagon) or 11-gon is an eleven-sided polygon. (The name hendecagon, from Greek hendeka “eleven” and –gon “corner”, is often preferred to the hybrid undecagon, whose first part is formed from Latin undecim “eleven”.)

### What is a shape with 1 million sides called?

megagon

### What is a 20 Gon?

In geometry, an icosagon or 20-gon is a twenty-sided polygon. The sum of any icosagon’s interior angles is 3240 degrees.

### What is a 19 sided shape called?

In geometry an enneadecagon or 19-gon is a nineteen-sided polygon. It is also known as an enneakaidecagon or a nonadecagon.

### What is a 15 sided shape called?

Convex, cyclic, equilateral, isogonal, isotoxal. In geometry, a pentadecagon or pentakaidecagon or 15-gon is a fifteen-sided polygon.

### Are 10 sided dice fair?

Or this 10-sided one. Or this 20-sided Roman die that is 1,800 years old. So long as there is an equally likely chance of landing on any face then they are Fair Dice.