Proportions

A proportion tells us that two ratios are the same. It is like saying two groups match in size even if their numbers look different. For example, 1 out of 2 is the same as 2 out of 4. Proportions help us solve puzzles with missing numbers.

How Proportions Work

When two ratios are equal, we say they are in proportion. You can check by multiplying across in a special way called cross multiplying. If both sides give the same answer, the ratios are equal. For example, 1/2 equals 3/6. Proportions are handy when you need to make something bigger or smaller.

Proportions in Real Life

People use proportions all the time. Cooks use them to double or halve a recipe. Painters use them to mix the right colors. Map makers use proportions to show big places on small paper. Doctors even use proportions to give the right amount of medicine. They help us keep things fair and correct.

Fun Facts

• The equal sign in a proportion means both sides are the same.
• Proportions are used by builders to make sure houses are the right size.
• Artists use proportions to draw people that look real.

Did You Know?

If you grow taller, the proportions of your body change slowly as you get older.