## Friday, November 13, 2009

### How I Stopped An Alien Invasion Using A Proportion

Alien's Proportion Lessons

So it was 12:00 midnight and very dim. Until it reached 12:01 and there were different colours of lights circling around outside, so with curiosity i went outside. When i got there i was shocked to see a group of aliens. They came up to me and threatened me that if i don't teach them and give them understanding about proportions they'll eat my food. Instead of them eating my food, i just gave them a short lesson.
1. I told them that "Proportion is a relationship that states two rates or ratios are equal".
2. Another thing i explained to them was that "Proportions can be written as a fraction" and "there are two different ways to find a proportion".
Page : 67
#6 Delia was paid \$35 for 5h of babysitting. How much should she recieve for 3 h? Use unit rate to find the answer.

Using A Ratio Table : Explanation
Make a ratio table, label one side with \$ and the other h for hours. Then under those labels put down the given information which would be \$35 under the \$ column and the 5h under the h column, which would leave us with "How much should she recieve in 3h?". Once you've already put the given information to solve the question, it's time to solve it. Since were looking for the price at 3h from 5h, we will need to find the unit rate because 5 and 3 aren't friendly numbers together. So to find the unit rate whatever you do to one side you do to the other so to find \$/h divide the \$ by 5 to get 1 and then the \$35 also by five and you'll get seven. From there we have to get to 21 hours, so we'll multiply each side with three and will end up with \$7 for 3h and there's your proportion.
Using A Ratio Table : Showing Work
(pictures not working but it's the same thing was what we've been doing in class)
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#21 David can saw a log into three pieces in 7min. If he continues sawing at a constant rate, how long will it take him to saw a similar log into six pieces?
Using A ratio table : Explanation
It's the same as the question above but dealing with a different situation and numbers. Instead of having \$/hr we'll have log/min. We start off with three pieces and minutes, to get to six from three pieces is pretty easy just multiply by 2, since you multiplied that side by two you do that to the other so from 3pcs/7mns, now we have 6pcs/21mns and that is your proportion "David will take 21 minutes to saw a similar log into 6 pieces.
#24
• a) Describe a pattern you can use to find the next fractions with the set of fractions given as information.

1/2, 2/4, 3/6, 4/8 - the pattern is increase the numerator by 1 value and increase the denominator by two.

5/6, 10/12, 15/18, 20/24 - the pattern is increasing the numerator by 5 and the denominator increases by its multiple.

THAT IS THE END :) Don't forget math test on proportions on monday :)