Nhờ mọi người giải ạ

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Nhờ mọi người giải ạ

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    Đáp án:

    \(A’B’ = 4cm\)

    Giải thích các bước giải:

    a) Do \(d > f \Rightarrow \) A’B’ là ảnh thật.

    b) Hình vẽ

    c) Ta có: 

    \(\begin{array}{l}
    \dfrac{{AB}}{{A’B’}} = \dfrac{{OA}}{{OA’}} = \dfrac{{12}}{{OA’}}\\
    \dfrac{{AB}}{{A’B’}} = \dfrac{{OI}}{{A’B’}} = \dfrac{{OF’}}{{OA’ – OF’}} = \dfrac{8}{{OA’ – 8}}\\
     \Rightarrow \dfrac{{12}}{{OA’}} = \dfrac{8}{{OA’ – 8}} \Rightarrow OA’ = 24cm\\
     \Rightarrow \dfrac{{AB}}{{A’B’}} = \dfrac{{12}}{{24}} = \dfrac{1}{2} \Rightarrow A’B’ = 4cm
    \end{array}\)

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