Plane Geometry


  1. PT is a tangent to a circle with centre O and radius 6 cm. If PT is 8 cm then length of OP is









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    As per the given in question , we draw a figure of circle with centre O and PT is a tangent

    Given that , OT = 6 cm. , TP = 8 cm.
    ∠OTP = 90°
    In ∆ OPT,

    Correct Option: A

    As per the given in question , we draw a figure of circle with centre O and PT is a tangent

    Given that , OT = 6 cm. , TP = 8 cm.
    ∠OTP = 90°
    In ∆ OPT,
    OP = √OT² + TP² = √6² + 8²
    OP = √36 + 64 = 100 = 10 cm.


  1. The chord AB of a circle of centre O subtends an angle θ with the tangent at A to the circle. Then measure of ∠ABO is :









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    On the basis of question we draw a figure of a circle with centre O

    Tangent ⇒ CAD
    OA ⊥ CD
    ⇒ OAD = 90° ∠BAD = θ = ∠OBA

    Correct Option: B

    On the basis of question we draw a figure of a circle with centre O

    Tangent ⇒ CAD
    OA ⊥ CD
    ⇒ OAD = 90° ∠BAD = θ = ∠OBA
    From ∆AOB ,
    ∴ ∠OAB = 90° – θ = ∠OBA



  1. O is the centre of a circle. P is an external point of it at a distance of 13 cm from O. The radius of the circle is 5 cm. Then the length of a tangent to the circle from P upto the point of contact is :









  1. View Hint View Answer Discuss in Forum

    As per the given in question , we draw a figure of circle with centre O and P is an external point of it at a distance of 13 cm from O

    Givne that , OT = 5 cm.
    OP = 13 cm.
    From ∆PTO ,
    ∴ PT = √OP² - OT²

    Correct Option: C

    As per the given in question , we draw a figure of circle with centre O and P is an external point of it at a distance of 13 cm from O

    Givne that , OT = 5 cm.
    OP = 13 cm.
    From ∆PTO ,
    ∴ PT = √OP² - OT²
    PT = √13² - 5²
    PT = √169 - 25 = √144 = 12 cm.


  1. If PQ and PR be the two tangents to a circle with centre O such that ∠QPR = 120°, then ∠POQ is :









  1. View Hint View Answer Discuss in Forum

    As per the given in question , we draw a figure of circle in which PQ and PR be the two tangents

    PQ = PR (Tangents from the same exterior point)
    Given , ∠QPR = 120°

    ∠OPQ = ∠OPR =
    120°
    = 60°
    2

    ∴ OQ ⊥ PQ (Tangent)

    Correct Option: C

    As per the given in question , we draw a figure of circle in which PQ and PR be the two tangents

    PQ = PR (Tangents from the same exterior point)
    Given , ∠QPR = 120°

    ∠OPQ = ∠OPR =
    120°
    = 60°
    2

    ∴ OQ ⊥ PQ (Tangent)
    From ∆OQP ,
    ∴ ∠OQP = 90°
    ∴ ∠POQ + ∠OPQ = 90°
    ∴ ∠POQ = 90° – 60° = 30°



  1. T is a point on the common tangents at P of two circles and if TA and TB are respectively the other tangents at A and B to the two circles drawn from the point T then









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    According to question , we draw a figure of two circles and T is a point on the common tangents at P

    We can say that tangents drawn from an external point to a circle are equal.

    Correct Option: B

    According to question , we draw a figure of two circles and T is a point on the common tangents at P

    We can say that tangents drawn from an external point to a circle are equal.
    ∴ TA = TP; TP = TB
    ∴ TA = TB