The radius of a circle is 15 cm and the length of one chord of the circle is 20 cm. What is the distance of the chord from the centre of the circle?
The radius of a circle is 15 cm and the length of one chord of the circle is 20 cm. What is the distance of the chord from the centre of the circle? Correct Answer 5√5 cm
Given:
The radius of the circle = 15 cm
The length of one chord of the circle = 20 cm
Formula Used:
(OC)2 = (OA)2 – (CA)2
Where OC → Distance of the chord from the centre of the circle
OA → Radius of the circle
CA → (1/2) × length of the chord
Calculation:
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In the given figure,
AB = 20 cm
CA = (1/2) × AB
⇒ (1/2) × 20
⇒ 10 cm
OA = radius = 15 cm
(OC)2 = (OA)2 – (CA)2
⇒ (OC)2 = 152 – 102
⇒ (OC)2 = 225 – 100
⇒ OC = √125
⇒ OC = 5√5 cm
∴ The distance of the chord from the centre of the circle is 5√5 cm.