# Intro to the Solver

The *Solver* is where you assemble the formulas you want to solve.

Once a formula has been added to the Solver, you can...

## An example

In this example, these two formulas were *added to the Solver*:

- Volume of a cylinder
- Volume of a sphere

There are several things of note:

- The formulas have been
*re-arranged*so that the formula 2 is on top - The formulas are
*grouped*together - In formula 2 (
*Volume of a sphere*), the variable*r*(radius) is the*output variable*, i.e. the variable that is solved for *r*in formula 2 is*linked*to*r*in formula 1- Several variablesâ€™
*units*have been switched from meters to centimeters - The variable
*V*in formula 2 (Volume of a sphere) has been*tagged*with the suffix*lower*