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Mathematics 16 Online
OpenStudy (anonymous):

Based on her findings, how much rope does she need? (Hint: Solve for h using the Geometric Mean Theorem).

OpenStudy (anonymous):

OpenStudy (anonymous):

In the figure, the large triangle and the two small triangles are all similar. That means the ratioof 6:12 is equal to the ratio 12:(h-6)

OpenStudy (anonymous):

So, this is like a geometric mean \[12^2 = 6(h-6)\]

OpenStudy (anonymous):

So I solve it like a algebra equation?

OpenStudy (anonymous):

Yes. The geometric mean thingie is just saying that \[\frac{12}{h-6} = \frac{6}{12}\]

OpenStudy (anonymous):

12 is the geometric mean of 6 and h-6

OpenStudy (anonymous):

Alright, the equation makes sense :) But I'm confused on how to solve the equation because of the h-6.

OpenStudy (anonymous):

Well, \[12 \times 12 = 6(h-6) = 6h - 36 \]

OpenStudy (anonymous):

can you solve for h

OpenStudy (anonymous):

Do I divide both sides by 6-h ?

OpenStudy (anonymous):

No, the next step is to add 36 to both sides

OpenStudy (anonymous):

So I add 36 to 144 ?

OpenStudy (anonymous):

Yes

OpenStudy (anonymous):

\[144 + 36 = 180 = 6x - 36 + 36 = 6x\]

OpenStudy (anonymous):

Do I divide 6x from both sides?

OpenStudy (anonymous):

Divide both side by 6, not 6x

OpenStudy (anonymous):

So I divide 6x by 6 ?

OpenStudy (anonymous):

Yep, and 180 too

OpenStudy (anonymous):

\[30=1x-36=36=6x\] So it looks like this now?

OpenStudy (anonymous):

I mean +36

OpenStudy (anonymous):

30=1x−36+36=6x

OpenStudy (anonymous):

We had \[144 + 36 = 180 = 6x - 36 + 36 = 6x\] we divide 180 and 6x by 6 and obtain \[\frac{180}{6} = \frac{6x}{6}\] \[30 = x\]

OpenStudy (anonymous):

A couple things. 1. I switched to x by mistake, it's supposed to be h. 2. We should substitute the answer into the original equation to check.

OpenStudy (anonymous):

So x=30 So H=30?

OpenStudy (anonymous):

We would still get 30 for H~ Am I right?

OpenStudy (anonymous):

Original problem was \[\frac{12}{h-6} = \frac{6}{12}\] We solved this and found h = 30 To check that, we compute h-6 = 24 and see whether the ratio looks correct: \[\frac{12}{24} =\frac{6}{12}\] And it does, both sides equal 1/2

OpenStudy (anonymous):

Thank you so much :)

OpenStudy (anonymous):

yw

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