1. PROPORTIONS 6-2

2. VOCABULARY Proportion – equality of two ratios Cross Products – the results when you cross multiply

3. KEY CONCEPTS In a proportion, the ratios and the cross products are equal to each other. Example: 6 = 8 ` 9 12 72 = 72

4. Examples… Tell whether the two ratios form a proportion. 1. 6 = 4 2. 15 = 5 9 6 20 7 36 = 36 yes 105 = 100 no

5. To solve a proportion that contains a variable, cross multiply. Example: x = 4 ` 9 6 6x = 36 Now you must get the x by itself, so reverse the operation. 6x = 36 6 6 x = 6

6. REAL WORLD PROBLEM 100 nautical miles equals about 115 standard miles. To the nearest mile, how far in standard miles is 156 nautical miles? Nautical miles Standard miles 100 = 156 115 m 100m = 17,940 100 100 m = 179.4  156 nautical miles is about 179 standard miles