Why A4 paper has odd dimensions

1
Why A4 paper has odd dimensions
The width-to-height ratio of A4 remains unchanged
when cut in half to make A5. What must the
ratio be?
a
b
b
a/2
length v2 x width
2
Surds Problem
Fold your paper as shown, and prove that length x
is equal to length y
Remember A4 paper has the same proportions when
cut in half, so
y
x
length v2 x width
3
Assume width 1, so length v2
v2
1 (v2 1)
2 v2
y
v2
1
x
v2 - 1
v2 - 1
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