📢 Too many exams? Don’t know which one suits you best? Book Your Free Expert 👉 call Now!


    Question

    Two circles of radius 13 cm and 15 cm intersect each

    other at points A and B. If the length of the common chord is 12 cm, then what is the distance between their centres?
    A √145 + √184 Correct Answer Incorrect Answer
    B √131 + √181 Correct Answer Incorrect Answer
    C √145 + √169 Correct Answer Incorrect Answer
    D √133 + √189 Correct Answer Incorrect Answer

    Solution

    Let O and R be the center of the circle and PQ be the length of the common chord. OP = 15, RP = 13 PS = 1/2 PQ (as perpendicular from the center of the circle to a chord bisects the chord) PS = 1/2 × 12 PS = 6 By applying Pythagoras theorem in PSO: OS2 = OP2-PS2 = 152 – 62 = 225-36 = 189   OS = √189   By applying Pythagoras' theorem in PSO': RS² = RP2-PS2 = 132 - 62 = 169-36 = 133 RS = √133 OR = OS + RS = √189 + √133 The distance between their centers = √189 + √133

    Practice Next

    Relevant for Exams:

    ask-question

    Not sure which exam is best for you Talk to our expert

    Get My Free Call