1. in a way that is appropriate or suitable in size, degree, or extent relative to something else
2. in amounts or shares that are fair and balanced according to a fixed ratio or relationship

Examples

• The tax burden should be distributed proportionately among all income levels.
• As the company grew, its expenses increased proportionately.
• The punishment was proportionately severe for the crime committed.
• Each partner receives profits proportionately to their investment.
• The recipe ingredients should be mixed proportionately to achieve the right flavor.
• Representation in the committee should be proportionately allocated to each region.