Based on her findings, how much rope does she need? (Hint: Solve for h using the Geometric Mean Theorem).
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)
So, this is like a geometric mean \[12^2 = 6(h-6)\]
So I solve it like a algebra equation?
Yes. The geometric mean thingie is just saying that \[\frac{12}{h-6} = \frac{6}{12}\]
12 is the geometric mean of 6 and h-6
Alright, the equation makes sense :) But I'm confused on how to solve the equation because of the h-6.
Well, \[12 \times 12 = 6(h-6) = 6h - 36 \]
can you solve for h
Do I divide both sides by 6-h ?
No, the next step is to add 36 to both sides
So I add 36 to 144 ?
Yes
\[144 + 36 = 180 = 6x - 36 + 36 = 6x\]
Do I divide 6x from both sides?
Divide both side by 6, not 6x
So I divide 6x by 6 ?
Yep, and 180 too
\[30=1x-36=36=6x\] So it looks like this now?
I mean +36
30=1x−36+36=6x
We had \[144 + 36 = 180 = 6x - 36 + 36 = 6x\] we divide 180 and 6x by 6 and obtain \[\frac{180}{6} = \frac{6x}{6}\] \[30 = x\]
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.
So x=30 So H=30?
We would still get 30 for H~ Am I right?
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
Thank you so much :)
yw
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