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Math Help - Geometry:Similar Triangles

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    Senior Member vaironxxrd's Avatar
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    Geometry:Similar Triangles

    Just want to know if i got this right guys. Im trying very hard now and i got serious with school im getting good grades ! thanks guys.
    But here i got this similar triangles questions. They are done... is just to know if im right


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    Forum Admin topsquark's Avatar
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    These triangles are not similar. 4/12 is not equal to 20/15.

    -Dan

    PS Okay, I appear to be wrong. I'll check out why later.

    Ah. I see now. That is a "y" not a 4. Please excuse.
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    Senior Member vaironxxrd's Avatar
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    Quote Originally Posted by topsquark View Post
    These triangles are not similar. 4/12 is not equal to 20/15.

    -Dan
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    Yes, that's fine.

    You can think of the sides of LMN are magnified by the exact same amount
    to be the sides of PQR.

    Let k be the magnification factor

    k[MN]=[QR]\Rightarrow\ k=\frac{[QR]}{[MN]}

    k[LM]=[PQ]\Rightarrow\ k=\frac{[PQ]}{[LM]}

    k[LN]=[PR]\Rightarrow\ k=\frac{[PR]}{[LN]}

    Therefore

    \frac{y}{12}=\frac{x}{18}=\frac{20}{15}

    or

    \frac{y}{20}=\frac{12}{15}

    \frac{x}{20}=\frac{18}{15}
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  5. #5
    Senior Member vaironxxrd's Avatar
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    Quote Originally Posted by Archie Meade View Post
    Yes, that's fine.

    You can think of the sides of LMN are magnified by the exact same amount
    to be the sides of PQR.

    Let k be the magnification factor

    k[MN]=[QR]\Rightarrow\ k=\frac{[QR]}{[MN]}

    k[LM]=[PQ]\Rightarrow\ k=\frac{[PQ]}{[LM]}

    k[LN]=[PQ]\Rightarrow\ k=\frac{[PQ]}{[LN]}

    Therefore

    \frac{y}{12}=\frac{x}{18}=\frac{20}{15}

    or

    \frac{y}{20}=\frac{12}{15}

    \frac{x}{20}=\frac{18}{15}
    Thanks i knew i was getting good at this. Sorry for not pointing out it was a fraction
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  6. #6
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    Note there was a typo in my post.
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    Senior Member vaironxxrd's Avatar
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    Quote Originally Posted by Archie Meade View Post
    Note there was a typo in my post.
    Sorry if i dont understand much but is TYPO an error?
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  8. #8
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    yes, a writing error, I had written PQ a 2nd time instead of PR.
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  9. #9
    Senior Member vaironxxrd's Avatar
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    NP Just have to thank you !
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