# Shapes & Geometry Shapes

Plane Geometry is about flat shapes like lines, circles and triangles … shapes that can be drawn on a piece of paper

Solid Geometry is about three dimensional objects like cubes, prisms, cylinders and spheres. Hint: Try drawing some of the shapes and angles as you learn … it helps. Đang xem: Geometry shapes

## Point, Line, Plane and Solid

A Point has no dimensions, only position A Line is one-dimensional A Plane is two dimensional (2D) A Solid is three-dimensional (3D)

## Why?

Why do we do Geometry? To discover patterns, find areas, volumes, lengths and angles, and better understand the world around us.

## Plane Geometry

Plane Geometry is all about shapes on a flat surface (like on an endless piece of paper).

Xem thêm: Student V. Placentia-Yorba

### Polygons

A Polygon is a 2-dimensional shape made of straight lines. Triangles and Rectangles are polygons.

Here are some more:

 Pentagon Pentagram Hexagon

### Symbols

There are many special symbols used in Geometry. Here is a short reference for you:

Geometric Symbols

Types of Angles

Transformations:

Symmetry:

Triangle Centers

## Trigonometry

Trigonometry is a special subject of its own, so you might like to visit:

## Solid Geometry

Solid Geometry is the geometry of three-dimensional space – the kind of space we live in …

Common 3D Shapes

### Polyhedra and Non-Polyhedra

There are two main types of solids, “Polyhedra”, and “Non-Polyhedra”:

Polyhedra (they must have flat faces):

 Cubes and Cuboids (Volume of a Cuboid)    Platonic Solids  Prisms   Pyramids

Non-Polyhedra (when any surface is not flat):

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