# Visualising Solid Shapes

#### Summary*arrow_upward*

Three dimensional objects or solids generally have length, breadth and height. Three dimensional objects look different from different locations or angles.

**Polyhedron**

A polyhedron is a solid shape bounded by polygons whereas non-polyhedrons do not have polygon shaped faces.

**Faces**

Polygons forming a polyhedron are known as its faces.

**Edges**

Line segments common to intersecting faces of a polyhedron

**are known as its edges.**

**Vertices**

**Reguler polyhedron**

A polyhedron is said to be regular if its faces are made up of regular polygons and the same number of faces meet at each vertex.

**Irregular polyhedron**

An irregular polyhedron is made of polygons whose sides and angles are not of equal measure.

F + V = E + 2 is known as Euler’s formula and it holds true for any polyhedron. Here F stands for faces, V for vertices and E for the edges of the polyhedron.

**Convex**

**polyhedron**

In a convex polyhedron, the line segment joining any two points on the surface of the polyhedron lies entirely inside or on the polyhedron.

**Concave polyhedron**

A polyhedron some of whose plane sections are concave polygons is known as a concave polyhedron. Concave polygons have at least one interior angle greater than 180° and has some of its sides bent inward.

**Prism**

A prism is a polyhedron with parallel congruent polygon bases and sides made of parallelograms.

**Pyramids**

A pyramid is a polyhedron whose base is a polygon of any number of sides and whose lateral faces are triangles with a common vertex.

Prisms and pyramids are named after the shape of their base.

Maps represent the location of a place or object in relation to other places or objects.

#### Videos*arrow_upward*

#### Questions & Answers*arrow_upward*

### 1 . Verify the Euler’s formula for a triangular prism.

Consider the triangular prism shown

Recall the Euler?s formula, F + V = E + 2

Here number of faces, F = 5

N...

### 2 . Verify Euler’s formula for the figure given below:

Recall the Euler?s formula, F + V = E + 2

From the given figure, we have

Number of faces, F = 12

Number of vertices,...

### 3 . Why are triangular shapes used while constucting towers,

It is not necessary that we should use triangles while constructing towers or bridges or houses etc.

### 4 . Names of five distinct polyhedrons

Please go through the following path to understand polyhedrons effectivley.

http://www.learnnext.com/CBSE-Class-VIII-Maths/L...

### 5 . what is a prism

The prism is type of glass has cogruent all sides, the light passes from prism it's curve in 20
^{0} to 40
^{0} degree bec...

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