Curriculum › Math ›Grade 6

Grade 6 Math · Level 2, Ratios, Rates & Percent

Proportions & Percent Change

How the lesson starts: Proportions & Percent Change

1. The Moonbeam Band

   Hi there! The Moonbeam Band is getting famous! Their small poster is 3 feet wide and 5 feet tall. Now they want a giant poster, 12 feet wide, with the exact same shape. How tall must it be? A proportion will tell us!

2. Proportions

   A proportion says two ratios are equal, like 3/5 = 12/20. Look at the bars: 3 of 5 parts, and 12 of 20 parts. The same amount is shaded! To solve 3/5 = 12/□, ask: 3 times what is 12? Times 4. So the bottom is 5 × 4 = 20.

3. Proportional or not?

   Is 2/3 = 7/9 true? Find the multiplier from the bottoms: 3 × 3 = 9. Then the top must be 2 × 3 = 6. But the top is 7, not 6. So 2/3 and 7/9 are not proportional. 2/3 and 6/9 would be!