1. AB is the diameter of the circle and C is a point on its circumference. According to the theorem, the angle subtended by a diameter at any point on the circle is 90°. Here, the diameter AB subtends ∠ACB at point C. Therefore, ∠ACB = 90°. Hence, the measure of ∠ACB is 90°.   For more NCERT SolutRead more

    AB is the diameter of the circle and C is a point on its circumference. According to the theorem, the angle subtended by a diameter at any point on the circle is 90°. Here, the diameter AB subtends ∠ACB at point C. Therefore,

    ∠ACB = 90°.

    Hence, the measure of ∠ACB is 90°.

     

    For more NCERT Solutions for Class 9 Maths Ganita Manjari Chapter 5 I’m Up and Down and Round and Round (2026-27):

    https://www.tiwariacademy.com/ncert-solutions/class-9/maths/ganita-manjari-chapter-5/

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  2. ABCD is a cyclic quadrilateral. According to the property of a cyclic quadrilateral, the sum of each pair of opposite angles is 180°. For angles A and C: ∠C = 180° - 75° = 105° For angles B and D: ∠D = 180° - 110° = 70° Therefore, ∠C = 105° and ∠D = 70°.   For more NCERT Solutions for Class 9 MRead more

    ABCD is a cyclic quadrilateral. According to the property of a cyclic quadrilateral, the sum of each pair of opposite angles is 180°.

    For angles A and C:

    ∠C = 180° – 75° = 105°

    For angles B and D:

    ∠D = 180° – 110° = 70°

    Therefore, ∠C = 105° and ∠D = 70°.

     

    For more NCERT Solutions for Class 9 Maths Ganita Manjari Chapter 5 I’m Up and Down and Round and Round (2026-27):

    https://www.tiwariacademy.com/ncert-solutions/class-9/maths/ganita-manjari-chapter-5/

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  3. PQRS is a cyclic quadrilateral, so its opposite angles P and R are supplementary. Therefore, (2x + 10) + (3x - 20) = 180 5x - 10 = 180 5x = 190 x = 38 Now, ∠P = 2(38) + 10 = 86° ∠R = 3(38) - 20 = 94° Hence, x = 38, ∠P = 86° and ∠R = 94°.   For more NCERT Solutions for Class 9 Maths Ganita ManjaRead more

    PQRS is a cyclic quadrilateral, so its opposite angles P and R are supplementary.

    Therefore,

    (2x + 10) + (3x – 20) = 180

    5x – 10 = 180

    5x = 190

    x = 38

    Now,

    ∠P = 2(38) + 10 = 86°

    ∠R = 3(38) – 20 = 94°

    Hence, x = 38, ∠P = 86° and ∠R = 94°.

     

    For more NCERT Solutions for Class 9 Maths Ganita Manjari Chapter 5 I’m Up and Down and Round and Round (2026-27):

    https://www.tiwariacademy.com/ncert-solutions/class-9/maths/ganita-manjari-chapter-5/

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  4. Draw perpendiculars from the centre to both chords. The radii are equal, and the perpendicular distances are also equal. Using the Baudhāyana–Pythagoras Theorem, the half-lengths of both chords are equal. Doubling these equal half-chords gives equal full chord lengths. Therefore, the two chords areRead more

    Draw perpendiculars from the centre to both chords. The radii are equal, and the perpendicular distances are also equal. Using the Baudhāyana–Pythagoras Theorem, the half-lengths of both chords are equal. Doubling these equal half-chords gives equal full chord lengths. Therefore, the two chords are equal, proving that AB = GF.

     

    For more NCERT Solutions for Class 9 Maths Ganita Manjari Chapter 5 I’m Up and Down and Round and Round (2026-27):

    https://www.tiwariacademy.com/ncert-solutions/class-9/maths/ganita-manjari-chapter-5/

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  5. Draw a perpendicular from the centre of the circle to the chord. It bisects the chord into two equal parts. Applying the Baudhāyana–Pythagoras Theorem to the right triangle, the half-chord is obtained as √13 cm. Doubling this value gives the full chord length. Therefore, the required chord length isRead more

    Draw a perpendicular from the centre of the circle to the chord. It bisects the chord into two equal parts. Applying the Baudhāyana–Pythagoras Theorem to the right triangle, the half-chord is obtained as √13 cm. Doubling this value gives the full chord length. Therefore, the required chord length is 2√13 cm.

     

    For more NCERT Solutions for Class 9 Maths Ganita Manjari Chapter 5 I’m Up and Down and Round and Round (2026-27):

    https://www.tiwariacademy.com/ncert-solutions/class-9/maths/ganita-manjari-chapter-5/

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    • 285