# How To

Tricky folds often require strange fractions, there are many techniques for achieving these.

Thirds

Fifths

Sevenths

• wonko says:

… so, budding mathematicians out there – WHY do these techniques work?

• Anugrah says:

because coordinate geometry deems it so ðŸ˜€

• Zaniel says:

you have right triangles and you basically use cosine to determine the length and then you could take that length and dived the full side of the paper and from that if you get whatever you wanted great. e.g. cos(78.75degrees)… (45+22.5+11.25) is .195 very close to .2 or 1/5.

• Bellairs from DeviantArt says:

Thirds:
If you plot the lines in a xy-plane, the x value is simply 1/3 (assuming that the sides of the square = 1.

Fifth:
Sorta the same thing. If you plot the lines out with the last one being at 11.25 degrees, it will just happen to go through (1/5,1)

Seventh:
I have no idea who figured this one out, but again, plot a line out to (1,1/7) and figure it out.

• D. Chen says:

Wow…why not just measure so u dont have extra folds?

• […] Well, Wonko of the Setting the Crease blog is here to the rescue! The blog’s author, Peter Whitehouse, was kind enough to post on his site a trick for folding paper into thirds, fifths and sevenths. Thank you! Check out his how-to post. […]

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