The radii of two concentric circles are 35 cm and 21 cm. If the chord of the greater circle is a tangent to the smaller circle, then the length of that chord is:
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 56 cm.
AC = √(OA2 - OC2) = √(352 - 212) = √(1225 - 441) = √784 = 28 cm
AB = 2 × AC = 2 × 28 = 56 cm
Hence, the length of the chord is 56 cm.