Friday, April 3, 2009

April 3,2008; Ms.Sa

Aim; How do we solve proportions by using cross product.?

1.)Explain; how the term cross product can help you remember how to solve a product.?
2/5= x/35
Fists you cross multiply.
Second you find the variable.
5÷70= 14

2.)Describe; the error in these steps: 2/3= x/12; 2x=36; x=18
First; They cross multiply wrong: 2(12)=24
Second; He had to put 3x=24: you had to divide 3÷24 and the answer would be x=8

3.)Show; how to use cross product to decide whether the ratios 6:45 and 2:15 are proportional.
You have to cross multiply 6(15)=90 and 45(2)=90
It has the same sum, so it is proportional.

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