## Faces Edges Vertices-3D Shapes- Euler's Geometry Formula

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Hello welcome to MooMooMath In this video I would like to talk about

Edges Vertices and Faces of a solid Face the flat surface of a solid

Edge- where two faces meet Vertices a point where two or more edges meet

If your solid is a rectangular solid then you can use a simple formula to find the edges,

vertices, and Faces Base + 2 = Number Faces

Base x 2 = Vertices Base x 3 = Edges

This cube is a rectangular solid and has a base of 4 sides

4 + 2 = 6 Number of Faces 4 x 2 = 8 Number of vertices

4 x 3 = 12 number of edges Unfortunately you can’t use this for all

solids There is another formula you can use for all

convex polyhedrons It is called Eulers formula used in Geometry

states, Face + Vertices – Edges = 2

Let’s look at some examples of Eulers Formula

Cube has 6 faces + 8 Vertices – 12 Edges = 14-12=2

Octahedron 8 faces + 6 Vertices – 12 Edges = 2

What about a cone? How many faces, edges, and vertices does a

cone have? What about cones and solid cylinders?

If you’re definition of a face will allow for a curve, then the cone will have 2 face

and 1 edges The solid cylinder will have two edges if

you allow the edge to be curved, and 3 faces 2 circle ones and a rectangle (if you take

the top and bottom off a tin can then cut the cylinder part on the seam and flatten

it out you would get a rectangle). and no vertices (no corners).