Geometry

Geometry is all about shapes and their properties.

If you like playing with objects, or like drawing, then geometry is for you!

Geometry can be divided into:

	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 and pyramids.

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

 

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)

Plane Geometry

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

	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

Types of Angles

Degrees (Angle) Radians Congruent Angles Parallel Lines and Pairs of Angles Transversal A Triangle Has 180° Supplementary Angles Complementary Angles

Angles Around a Point Angles on a Straight Line Interior Angles Exterior Angles Interior Angles of Polygons Exterior Angles of Polygons

 

Using Drafting Tools Geometric Constructions Using the Protractor Using the Drafting Triangle and Ruler Using a Ruler and Compass

 

	Transformations and Symmetry Transformations: Rotation Reflection Translation Resizing Symmetry: Reflection Symmetry Rotational Symmetry Point Symmetry Lines of Symmetry of Plane Shapes 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

	Pythagoras Pythagoras' Theorem Pythagorean Triples
	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: Introduction to Trigonometry Trigonometry Index

 

Solid Geometry

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

Let us start with some of the simplest shapes:

• Cube
• Cuboid
• Volume of a Cuboid

Solids come in two types "Polyhedra" and "Non-Polyhedra":

	Polyhedra : (they must have flat faces)	Platonic Solids Prisms Pyramids
	Non-Polyhedra: (if any surface is not flat)	Sphere Torus Cylinder Cone

	Vertices, Faces, and Edges
	Euler's Theorem