Geometry & Trig Reference
Math formulas, definitions, properties, diagrams and examples from Geometry and Trigonometry
Geometry Stuff | |
Perimeters | Areas |
Circle Stuff | |
The Geometry of Circles: Definitions and formulas for the radius of a circle, the diameter of a circle, the circumference (perimeter) of a circle, the area of a circle, the chord of a circle, arc and the arc length of a circle, sector and the area of the sector of a circle | The Trigonometry of Circles: Definitions and formulas for the arc and the arc length of a circle, sector and the area of the sector of a circle, the unit circle, the angles on the unit circle in radians, the angles on the unit circle in degrees, the points on the circumference of the unit circle |
Triangle Stuff | |
Notations: Geometry notations for triangles including the right triangle, congruent sides of a triangle and congruent angles of a triangle | The Geometry of Triangles: Definitions and formulas for the area of a triangle, the sum of the angles of a triangle, the Pythagorean theorem, Pythagorean triples and special triangles (the 30-60-90 triangle and the 45-45-90 triangle) |
Types of Triangles: Definitions and formulas for triangles including right triangles, equilateral triangles, isosceles triangles, scalene triangles, obtuse triangles and acute triangles | The Trigonometry of Triangles: Definitions and formulas for basic trigonometry, sine, cosine, tangent, cosecant, secant, cotangent, the law of sines and the law of cosines |
Quadrilateral Stuff: Definitions and formulas for perimeter and area, properties of sides and angles, diagrams | |
Squares | Rhombuses (Rhombi) |
Rectangles | Kites |
Parallelograms | Trapezoids |
Properties of Polygons: Information on properties, interior angles and central angles | ||
Triangles | Quadrilaterals | Pentagons |
Hexagons | Heptagons | Octagons |
Nonagons | Decagons | 11-gons |
Dodecagons |
Properties of Polyhedra:
Information on properties, faces, edges and dihedral angles
To see all the images of the polyhedra at once, check out my Polyhedra Gallery.
The Five Platonic Solids |
Tetrahedron | Cube | Octahedron | Dodecahedron | Icosahedron |
The Thirteen Semi-Regular Platonic Solids |
truncated tetrahedron | truncated cube | truncated octahedron | truncated dodecahedron | truncated icosahedron |
The Cubocta Family of Platonic Solids |
cuboctahedron | rhombicuboctahedron | snub cuboctahedron | truncated cuboctahedron |
The Icosidodeca Family of Platonic Solids |
icosidodecahedron | rhombicosidodecahedron | snub icosidodecahedron | truncated icosidodecahedron |
The Stellated Family of Platonic Solids |
stellated cuboctahedron | stellated icosidodecahedron | small stellated dodecahedron | great stellated dodecahedron |
Geomentry and Trigonometry Lessons Tessellations Damping Functions The Geometry of Crop Circles Interior Angles of Polygons The Pythagorean Identities What's a Limit? |