Proportionally means in a way that keeps the right relationship or balance between different parts. When something changes proportionally, all its parts grow or shrink together in the same way, maintaining their relative sizes.

Imagine you're enlarging a drawing on a copy machine. If you increase the width proportionally, the height increases by the same percentage, so the picture doesn't look stretched or squashed. A square stays square, and a circle stays round. But if you only make it wider without adjusting the height proportionally, you'd end up with a distorted mess.

The word shows up in fairness discussions too. If a teacher assigns homework proportionally to how much class time was spent on each topic, students won't get twenty problems on something they barely covered. When splitting a pizza bill, paying proportionally means each person pays based on how many slices they ate, not the same flat amount.

In science and math, relationships are often proportional. If you're mixing paint and need twice as much, you must increase each color proportionally: doubling the blue means doubling the yellow too, or your green will come out wrong. The key idea is keeping everything in proper balance, so nothing gets out of whack as things change.