Improved function, shopping (Worksheets) and sharing in the works!
Update will be available by July 15, 2013.

The spinner is finger rotated.

Preschool to University all-in-one Math App:

INSTRUCTIONS:
1) TIME CLOCK:
The tip of the spinner locates your “YOU ARE HERE” (time of day) position while looking down on the earth from above the North Pole.
Note: The earth is spinning very fast!
2) ANGLE MEASURE:
The Radian angle values scroll dynamically while the spinner is rotated. Equivalent Gradian and Degree values are indicated statically (multiply the Hour Factor by the desired Angle Unit).
Note: A Radian is a unit of angle measure created at the circle center when a radius length is laid upon the circle perimeter, and radius lines from the circle center are extended to each end of that arc.
3) CIRCLE GEOMETRY:
Equations for circumference arc (length) and circle sector (area) are stated with their respective values that scroll dynamically as the spinner is finger-rotated.
Note: These two equations use Radian angle value because the Radian is integral to the circle construct. Degrees and Gons are arbitrary divisions of a circle into angles.
4) TRIGONOMETRY:
Sine and cosine tracking dots follow their respective graphs as the spinner is rotated.
The design gives the ‘on-the-hour’ right-triangle side lengths for use in all six trigonometry equations.
NOTE: The sine of any given angle (theta, θ) is the length of its vertical side [of the triangle that is formed in the image] divided by the length of its hypotenuse.