Plane Geometry
If you like drawing, then geometry is for you!
Plane Geometry is about flat shapes like lines, circles and triangles ... shapes that can be drawn on a piece of paper
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 onedimensional
A Plane is two dimensional (2D)
A Solid is threedimensional (3D)
Plane Geometry is all about shapes on a flat surface (like on an endless piece of paper).
 Quadrilaterals (Rhombus, Parallelogram, etc)
 Rectangle, Rhombus, Square, Parallelogram, Trapezoid and Kite
 Interactive Quadrilaterals
 Shapes Freeplay
Polygons
A Polygon is a 2dimensional shape made of straight lines. Triangles and Rectangles are polygons.
Here are some more:
The Circle
 Circle
 Pi
 Circle Sector and Segment
 Circle Area by Sectors
 Annulus
 Activity: Dropping a Coin onto a Grid
Circle Theorems (Advanced Topic)
Symbols
There are many special symbols used in Geometry. Here is a short reference for you:
Congruent and Similar
Angles


Using Drafting Tools 
Transformations and Symmetry
Coordinates
More Advanced Topics in Plane Geometry
Pythagoras
Conic Sections
Trigonometry
Trigonometry is a special subject of its own, so you might like to visit: