Plane Geometry


  1. ABCD is a cyclic trapezium in which AD || BC. If ∠ABC = 70°, then ∠BCD is









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    As per the given in question , we draw a figure cyclic trapezium ABCD

    As we know that the sum of the opposite angles of a concyclic quadrilateral is 180°.
    ∴ ∠ABC + ∠ADC = 180°
    ⇒ 70° + ∠ADC = 180°
    ⇒ ∠ADC = 180° – 70° = 110°
    ∵ AD || BC
    ∴ ∠ADC + ∠BCD = 180°

    Correct Option: C

    As per the given in question , we draw a figure cyclic trapezium ABCD

    As we know that the sum of the opposite angles of a concyclic quadrilateral is 180°.
    ∴ ∠ABC + ∠ADC = 180°
    ⇒ 70° + ∠ADC = 180°
    ⇒ ∠ADC = 180° – 70° = 110°
    ∵ AD || BC
    ∴ ∠ADC + ∠BCD = 180°
    ⇒ 110° + ∠BCD = 180°
    ⇒ ∠BCD = 180° – 110° = 70°.


  1. AB is a diameter of a circle having centre at O. PQ is a chord which does not intersect AB. Join AP and BQ. If ∠BAP = ∠ABQ, then ABQP is a :









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    AB is a diameter of a circle having centre at O. PQ is a chord which does not intersect AB ,

    Correct Option: B

    AB is a diameter of a circle having centre at O. PQ is a chord which does not intersect AB ,

    ∠PAB = ∠ABQ
    ∴ PQ || AB



  1. If ABCD be a rhombus, AC is its smallest diagonal and ∠ABC = 60°, find length of a side of the rhombus when AC = 6 cm.









  1. View Hint View Answer Discuss in Forum

    According to question , we draw a figure of rhombus ABCD in which AC is its smallest diagonal

    ∠ABC = 60°
    AB = BC

    Correct Option: A

    According to question , we draw a figure of rhombus ABCD in which AC is its smallest diagonal

    ∠ABC = 60°
    AB = BC
    ∴ ∠BAC = ∠BCA = 60°
    ∴ ∆ ABC is an equilateral triangle.


  1. ABCD is a cyclic trapezium whose sides AD and BC are parallel to each other. If ∠ABC = 75° then the measure of ∠BCD is :









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    As per the given in question , we draw a figure cyclic trapezium ABCD

    Given , ∠ABC = 75°
    ABCD is a concyclic quadrilateral.
    AD || BC
    ∴ ∠DAB + ∠ABC = 180°
    ⇒ ∠DAB = 180° – 75° = 105°
    Sum of the opposite of a concyclic quadrilateral = 180°

    Correct Option: A

    As per the given in question , we draw a figure cyclic trapezium ABCD

    Given , ∠ABC = 75°
    ABCD is a concyclic quadrilateral.
    AD || BC
    ∴ ∠DAB + ∠ABC = 180°
    ⇒ ∠DAB = 180° – 75° = 105°
    Sum of the opposite of a concyclic quadrilateral = 180°
    ∴ ∠BAD + ∠BCD = 180°
    ⇒ 105° + ∠BCD = 180°
    ⇒ ∠BCD = 180° – 105° = 75°



  1. If PQRS is a rhombus and ∠SPQ = 50°, then ∠RSQ is









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    On the basis of question we draw a figure of rhombus ABCD

    In the rhombus PQRS,
    PQ = QR = RS = SP
    ∠SPQ = 50°

    ∴ ∠PSQ = ∠PQS =
    180° - 50°
    2

    Correct Option: B

    On the basis of question we draw a figure of rhombus ABCD

    In the rhombus PQRS,
    PQ = QR = RS = SP
    ∠SPQ = 50°

    ∴ ∠PSQ = ∠PQS =
    180° - 50°
    2

    ∠PSQ = ∠PQS =
    130°
    = 65°
    2

    ∠PSR = 180° – 50° = 130°
    ∠RSQ = 130° – 65° = 65°