1. Direct Proportions Developed by Ivan Seneviratne

2. Proportions A proportion is an equation that states the equality of two rates or ratios. In other words, a proportion is an equation with a ratio on each side. Example 3/4=6/8 Two quantities are in direct proportion when they increase or decrease in the same ratio. The cross- products method, can be used to solve a proportion problem.

3. The Cross-Products Method (read “a is to b as c is to d”) Means-extremes property: Product of the means is equal to the product of the extremes where a, d are the extremes and b, c are the means.

4. Problem Justin was a great chef. He worked at a fabulous restaurant in Paris. His customers ate snails to snake skins at a ratio of 3 to 7. If they ate 40 snake skins, how many snails did they eat? Uncompleted Situation Complete Situation Snails Snake 3 7 Uncompleted Situation Complete Situation Snails 42 3 7 Cross Multiply Snails 3 7 42 They ate 18 snails

5. 1.Jonathan became a great golf player. He won 7 games to 4 that he lost. If he won a total of 42 games, how many did he lose? 2.Cecil talked 18 times to the 12 times that John talked. If Cecil talked a total of 72 times, how many times did John talk? 3.Felix cycled 4 km in 24 min. At this rate, how long does he take to cycle 10 km? Your Turn 24 games 48 times 60 min

6. This presentation is developed by Ivan Seneviratne © 2008 purely for personal use. ivanthexplorer@yahoo.co.uk