Grammar
Style guide 
proportional and proportionate
Both proportional and proportionate mean properly related in size, degree or other measurable way, i.e. in proportion. However, proportional has a specific mathematical meaning that proportionate doesn’t. For instance, you could say:
- The field strength is proportional to the transmitted power.
- The concentration of the final solution is proportional to the amount of solute.
- The force on the pinion is proportional to the length of the lever and the applied force.
You could not use proportionate in any of these examples.
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