Question

    In ΔPQR, PQ = 4 cm, QR = 3 cm, and RP = 3.5 cm. ΔDEF

    is similar to ΔPQR. If EF = 9 cm, what is the perimeter of ΔDEF?
    A 10.5 cm Correct Answer Incorrect Answer
    B 21 cm Correct Answer Incorrect Answer
    C 31.5 cm Correct Answer Incorrect Answer
    D None of these Correct Answer Incorrect Answer

    Solution

    Given, △ PQR ∼△ DEF ⇒ PQ/DE = QR/EF = RP/FD Since, PQ/DE = QR/EF ⇒ 4/DE = 3/9 ⇒ DE = 12 cm Similarly, QR/EF = RP/FD ⇒ 3/9 = 3.5/FD ⇒ FD = 10.5 cm ∴ Perimeter of △ DEF = DE + EF + FD = 12 + 9 + 10.5 = 31.5 cm

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