Guitar plans

[CrackedPepper]

I picked up a set up drwaings/plans for a future build.  The plans are 2/3 scale.  If I want to have the plans blown up to full scale, what do I ask for?  My initial reaction to get the plans blown up by 33% but maybe that is incorrect?  What would the enlargment percentage be if I wanted a 7/8 scale guitar?  Any thoughts?

 

[bob7point7]

To blow it up to full size you would want to reverse the 2/3 scale, so you would go 3/2, which means blowing it up 50%. To go with 7/8 scale you'd want to to go to 21/16, which means blowing it up 31.25%.

 

[CrackedPepper]

Thanks bob7point7 - that checks my calculations.  I had done it this way:

What times 2/3 = 1 or algebraically:
x * .6667 = 1 
x = 1/.6667 
x = 1.5

x * 2/3 = 7/8 or x * .6667 = .875
x = .875/.6667
x = 1.3125

Your way is even easier to understand so thanks for teaching me something new!