ЁЯУв Too many exams? DonтАЩt know which one suits you best? Book Your Free Expert ЁЯСЙ call Now!

    Question

    In a triangle ABC, AD is the altitude from A to BC. If

    AD = 12 cm, AB = 13 cm, and AC = 14 cm, find the length of BC.
    A 18 cm Correct Answer Incorrect Answer
    B 12.2 cm Correct Answer Incorrect Answer
    C 20 cm Correct Answer Incorrect Answer
    D 21 cm Correct Answer Incorrect Answer

    Solution

    Using Pythagoras' theorem on triangles ABD and ACD: Let BD = x and DC = y, so BC = x + y. From triangle ABD: AB┬▓ = AD┬▓ + BD┬▓ 13┬▓ = 12┬▓ + x┬▓ 169 = 144 + x┬▓ x┬▓ = 25 тЖТ x = 5 cm. From triangle ACD: AC┬▓ = AD┬▓ + DC┬▓ 14┬▓ = 12┬▓ + y┬▓ тЖТ 196 = 144 + y┬▓ y┬▓ = 52 тЖТ y = тИЪ52 тЙИ 7.21 cm. BC = x + y = 5 + 7.21 = 12.21 cm.

    Practice Next
    More Triangle Questions
    ask-question