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, cylinders and spheres.
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)
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).
- Quadrilaterals (Rhombus, Parallelogram, etc)
- Rectangle, Rhombus, Square, Parallelogram, Trapezoid and Kite
- Interactive Quadrilaterals
- Parallelogram In Any Quadrilateral
- Paper Sizes
- Shapes Freeplay
Polygons
A Polygon is a 2-dimensional shape made of straight lines. Triangles and Rectangles are polygons.
Here are some more:
The Circle
- Circle
- Pi
- Circle Area by Lines
- Circle Sector and Segment
- Circle Area by Sectors
- Activity: Dropping a Coin onto a Grid
- Arc
- Annulus
Circle Theorems (Advanced Topic)
Symbols
There are many special symbols used in Geometry. Here is a short reference for you:
Congruent and Similar
Angles
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Using Drafting Tools
- Geometric Constructions
- Using the Protractor
- Using the Drafting Triangle and Ruler
- Using a Ruler and Compass
Transformations and Symmetry
Coordinates
More Advanced Topics in Plane Geometry
Pythagoras
Conic Sections
Circle Theorems
- Circle Theorems
- Tangent and Secant Lines
- Intersecting Secants Theorem
- Intersecting Chords Theorem
- Angle of Intersecting Secants Theorem
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 ...
... let us start with some of the simplest 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) |
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Platonic Solids | |
Prisms | |
Pyramids |
Non-Polyhedra (when any surface is not flat):
Sphere | Torus | |||
Cylinder | Cone |
- Polyhedron Models
- Volume and Area of a Sphere Calculator
- Spheroid
- Cross Sections
- Vertices, Faces, and Edges
- Cone vs Sphere vs Cylinder
- Pyramid vs Cone
- Prism vs Cylinder
- Pyramid vs Cube
- Volume of Horizontal Cylinder
- Euler's Theorem
- Pythagoras in 3D
- Hypercubes
- Builder's Math
- Moments of Area