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A circle has a radius of 15 cm. A chord is drawn. The distance from the centre of the circle to the chord is 9 cm. What is the length of the chord?
The radius of the circle is 15 cm and the perpendicular distance from the centre to the chord is 9 cm. The perpendicular from the centre to a chord bisects the chord. Thus, half of the chord forms a right triangle. Half chord = √(15² - 9²) = √(225 - 81) = √144 = 12 cm Therefore, length of the chordRead more
The radius of the circle is 15 cm and the perpendicular distance from the centre to the chord is 9 cm. The perpendicular from the centre to a chord bisects the chord. Thus, half of the chord forms a right triangle.
Half chord = √(15² – 9²)
= √(225 – 81)
= √144
= 12 cm
Therefore, length of the chord = 2 × 12 = 24 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/
See lessProve that the perpendicular bisector of a chord passes through the centre of the circle.
Let AB be a chord of a circle with centre O. Join OA and OB. Since OA and OB are radii of the same circle, OA = OB. Thus, O is equidistant from the two endpoints A and B of the chord. The locus of points equidistant from A and B is the perpendicular bisector of AB. Therefore, the perpendicular bisecRead more
Let AB be a chord of a circle with centre O. Join OA and OB. Since OA and OB are radii of the same circle, OA = OB. Thus, O is equidistant from the two endpoints A and B of the chord. The locus of points equidistant from A and B is the perpendicular bisector of AB. Therefore, the perpendicular bisector of chord AB passes through the centre O of the circle. Hence proved.
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/
See lessThe diameter of a circle is AB. Point C is on the circumference. What is the measure of the ∠ACB? Explain your reasoning.
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/
See lessABCD is a cyclic quadrilateral inscribed in a circle. If ∠A measures 75°, what is the measure of ∠C? If ∠B measures 110°, what is the measure of ∠D?
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/
See lessQuadrilateral PQRS is inscribed in a circle. If ∠P = (2x + 10)° and ∠R = (3x – 20)°, find the value of x and the measures of ∠P and ∠R.
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/
See less