Ratio Equation Program

[Joe Horn]

Here's an even shorter program that takes the 3 known values, entered on the stack in either clockwise or counterclockwise order, starting from the unknown but skipping it. For example, if this is the equation: \(\frac { 51 }{ 57 } =\frac { 68 }{ x } \), then you'd enter the values either of these two ways:

57 ENTER 51 ENTER 68 [clockwise]
68 ENTER 51 ENTER 57 [counterclockwise]

Then run this program:

Code:

001 ÷
002 ÷

Of course, cross-multiplying and then dividing also takes only two operations, but I like the circular input pattern of this RPN-friendly method.