Smile 發問於 科學及數學數學 · 4 月 前

Maths problem, thankd?

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2 個解答

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  • SC147
    Lv 6
    4 月 前
    最佳解答

    From △BAE :

    ∵AB=AE, ∴△BAE is an isos.△ => base∠s equal

    Let the base∠ be θ

    2θ+112° = 180°

    ∴θ= 34°

    So, ∠DCF=∠ABE =θ=34° (corr.∠s equal)

    Let AB=DA= 1 unit

    Let DF = x,

    Then FA= 1-x

    From △DCF : tan∠DCF = x/1

            ∴ x = tan 34°

    From △ABF, tan∠ABF = (1-x)/1 = 1-tan 34°

          ∴∠ABF = 18°    Ans. (B)

  • 4 月 前

    The Answer is

    D. 26

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