Scratch

Here is Scratch's most extensive formula solver.

This amazing program is able to Perimeter, Surface Area (2D/3D), Volume, Circumference, Arc Length, Area of a Sector, Central Angle of a Polygon, and Geometric Probability (Fraction, Decimal, Percent).

For the Area and Volume it also has a ton of different shapes to choose from.

This is a much quicker alternative to find answers to questions without typing all the formulas into a calculator.

LINK: http://scratch.mit.edu/projects/Dom818/1714748