# Plane Geometry

If you like drawing, Geometry is for you!

 Plane geometry is all about shapes like lines, circles and triangles ... shapes that can be drawn on a flat surface called a Plane (it is like on an endless piece of paper).

## 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)

Hint: Try drawing some of the shapes and angles as you learn ... it helps.

### Shapes

 2D Shapes Activity: Sorting Shapes Triangles Right Angled Triangles Interactive Triangles Quadrilaterals (Rhombus, Parallelogram, etc) · Rectangle, Rhombus, Square, Parallelogram, Trapezoid, Kite Interactive Quadrilaterals Shapes Freeplay Perimeter Area Area of Plane Shapes Area Calculation Tool Area of Polygon by Drawing Activity: Garden Area General Drawing Tool

### Polygons

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

Here are some more:

 Properties of Regular Polygons Diagonals of Polygons Interactive Polygons

### The Circle

 Circle Pi Circle Sector and Segment Circle Area by Sectors Annulus (Advanced) Circle Theorems Activity: Dropping a Coin onto a Grid

### Symbols

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

### Congruent and Similar

 Congruent Shapes Similar Shapes

### Angles

 Acute Angles Right Angles Obtuse Angles Straight Angle Reflex Angles Full Rotation

### Using Drafting Tools

Geometric Constructions

### Transformations and Symmetry

Symmetry Artist

Activity: Symmetry of Shapes
Activity: Make a Mandala
Activity: Coloring (The Four Color Theorem)

Tessellations
Tessellation Artist

### Coordinates

Cartesian Coordinates
Interactive Cartesian Coordinates
Hit the Coordinate Game

## More Advanced Topics in Plane Geometry

### Conic Sections

Set of all points
Conic Sections
Ellipse
Parabola
Hyperbola

### Trigonometry

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