Pythagorean Addition

TL;DR: Instead of labouriously computing (c = \sqrt{a^2 + b^2}), we can mentally calculate using the alpha-max plus beta-min algorithm, by estimating

[\hat{c} = \mathrm{max}\left(a, 0.9a + 0.5b \right)]

and this will be very close to the actual (c). This is useful for adding up sources of variance, or figuring out radiuses, or other such things.

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