Setting an angle exactly

I want to model a Mayan pyramid and make the walls all be at a 64° angle upwards, how do I set the wall to the exact angle I want?
I know how to view edge angles but I need to change them exactly.

When you rotate something you can type in a number to rotate a specific amount. For example ‘r’ -> ‘25’ would rotate an object 25 °. You can also specify around which axis to rotate ‘r’ -> ‘x’ -> 25 would rotate an object 25 ° around the x-axis