If you are trying to build something at a slope of 23 degrees, you will need the rise and the run to be in a ratio of .4244748162...
That number is the tangent of 42 degrees. That is probably more decimal places than you need. You can take more or fewer depending on how accurate it has to be.
Let's say you take two decimal places, so you want the ratio of the rise to the run to be .42. That means build it up 42 inches or feet or meters or whatever, depending on the scale of the thing, for every 100 inches long it is.
So for every 100 units of length, there should be 42 units of height.
If you want it to be more acurate, you can do 424 units of height for every 1000 units of length.
Get it?
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