Lesson 5.5: Similar Figures and Proportions was introduced, modeled, and practiced. Students learned about corresponding sides and angles to help with determining whether two figures were proportional.
SIMILAR FIGURES
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If two figures are similar, then the measures of the corresponding angles are equal and the ratios of the lengths of the corresponding sides are proportional.
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P.O.N. 12.03.14
Marc is 5 foot tall and casts a shadow that is 3 foot long. He is standing next to a tree that casts a 20 foot long shadow. Use the information to find the height of the tree to the nearest tenth of a foot.
Answer to P.O.N. 12.02.14
There will be 9000 Crayola Crayons made in 15 minutes. I would set up a proportion and use cross-product: 2400/4 = p/15. The cross-products give you 24(15) = 4p. You end up with 36000 divided by 4 which equals 9000 crayons.- understand the concept of a ratio.
- use ratio language to describe a ratio relationship between two quantities.
For Evening Practice, the student is expected to...
- complete page 21 and 22.
To answer this problem you need to do a ratio so the ratio of Marc is 5:3 since the height of the tree is unknown we will use a variable so x will be the height of the tree so the ratio will be x:20 since both ratios are using height it will be 5/3 = x/20 so we need to cross multiply and 5*20 is 100 it is 100 = 3x if we divided by three on each side it will be 33 1/3 so rounded to the nearest tenth the tree is 33.3 ft tall
ReplyDeleteAdam Kelly 4
Adam,
DeleteNice work on using a proportion to solve this problem. You should be successful with today's lesson based on this question.
I think the shadow of the tree would be 12 feet long. I did this by first dividing 5 by 5 and 3 by 5 first because I wanted to know the shadow height for a 1 foot tall object. Doing that, I got 1 foot equals a .6 shadow. Then, I multiplied .6 by 20 and 1 by 20 because I want to know the shadow for a 20 foot tree. That gave me the answer of a 12 foot long shadow for a 20 foot long tree.
ReplyDeleteGibel
Gibel,
DeleteUse a proportion to help you out with this problem. You tree's height is a little short.
The answer that I got is 3. with a line over top of the 3. I got my answer by making 5 foot tall and 3 foot long into a fraction that looks like this, 5/3. Then after I did that I knew that the tree casted a shadow of 20 feet long and they didn't know how tall it was. So what I did was then made 20 into a fraction like this "m/20". I put "m" in their because that is what we are solving for. Then I cross multiplied. I did 20 times 5 which is 100 and I did 3 times "m" which we don't know what "m" so we just turned it into an algebraic equation. The problem now looks like 100=3m. Next to see what "m" is we have to isolate is and since you have to multiply 3 and "m" you would do the opposite in an equation. Then you would divide 100 by 3 and you would get .3 with a line on top of the 3 which tells you that it is run on.
ReplyDeleteyour fav,
Knickscalention
Knickscalention,
DeleteI love the proportion that you established. What cost was the division of 100 by 3. Look back at your answer and see it 3 will truly only go into 100 only 3 times.