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Question
A chord is at a distance of 15 cm from the centre of the circle of radius 25 cm. The length of the chord is
Options
25 cm
20 cm
40 cm
18 cm
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Solution
40 cm
Explanation;
Hint:
In the right triangle OAC,
AC2 = OA2 – OC2
= 252 – 152
= (25 + 15)(25 – 15)
= 40 × 10
AC2 = 400
AC = `sqrt(400)`
= 20
Length of the chord AB = 20 + 20 = 40 cm.
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