比例: a proportional relationship and a tendency to change
Read a stated proportional relationship such as circumference and diameter, without turning every ば〜ほど tendency into an exact mathematical proportion.
A relationship stated as proportional
比例, read ひれい, means proportion. 円の周りの長さは直径に比例する。 says that a circle’s circumference is proportional to its diameter.
In this relationship, doubling the diameter doubles the circumference. Both change by the same factor; circumference and diameter are not equal lengths.
The qualification nearly
売上は客の数にほぼ比例して増えた。 reports sales increasing almost in proportion to customer numbers. ほぼ qualifies the relationship as approximate.
Without numerical data, this does not establish a fixed amount of sales per customer. Keep the qualification almost when reading a real-data relationship.
A tendency expressed by increasing degree
練習すればするほど、上手になります。 expresses becoming more skilled with more practice. It does not supply a formula in which skill and practice change by exactly the same factor.
Distinguish a relationship stated with 比例する from a grammatical expression of degree-dependent change. Do not calculate every simultaneous increase as an exact proportion.
Does 練習すればするほど、上手になります。 let you calculate exactly twice the skill from twice the practice?
Show the answer and why
No. It expresses a tendency, without giving an exact proportional formula for skill and practice.