angle sum = (n-2)*180 n is number of sides

Origin; on a flat x-y coordinate plane, the original, sometimes marked as O is usually (0, 0)

On a x-y-z coordinate system, then the origin is usually (0, 0, 0)

A point has no dimension, only position. A line is one dimension. A plane is two dimension. A solid is three dimension.

Perimeter Just add all sides of polygon

Area Square = \(s^2\)

Parallelogram (rectangle is one such) = length * width

Plane Geometry

Quadrilaterals

Rectangle, Rhombus, Square, Parallelogram, Trapezoid and Kite

Polygons

Solid Geometry

Volume Cube = \(s^3\) Rectangular prism = \(L * W * H\) Cylinder = area of base * height Cone = \(\frac{1}{3} * \pi r^2 * height\) Pyramid = \(\frac{1}{3} * area of base * height\)

“The key difference between cube and cuboid is: a cube has six square-shaped faces of the same size but a cuboid has rectangular faces.”

Circles

Circle: \((x-h)^2 + (y-k)^2 = r^2\) (where (h, k) = the center and r = radius)

Circle area = \(\pi R^2 (R = radius)\) Sphere = \(\frac{4}{3} * \pi r^3\) \(\pi\)

Right angle

Straight angle

Acute angle

Obtuse angle

Reflex angle

Full rotation

Degrees to radians rad = \(\frac{\pi}{180^o} (^o)\)

Radians to degrees \(^o = \frac{rad}{\pi} (180^o)\)

Arc

Positive angle

Negative angle

Unit Circle

Differential Geometry

Information Geometry