noun
proportional; in proportion to
Used in computing and technical contexts to describe something that changes in proportion to another quantity. Often appears as a modifier before nouns.
比例に応じて変化する値。
A value that changes in proportion.
比例に応じて割り当てる。
Allocate in proportion.
に応じて is a general pattern meaning 'according to' or 'in response to'; 比例に応じて specifically means 'in proportion to'.
Compound of 比例 (proportion) + に応じて (according to). The exact historical derivation is straightforward; the phrase is a standard modern construction.