CBSE2026Class Class 10 · Mathematics2 Marks · Short✅ Verified
Two concentric circles are of radii 5 cm and 4 cm. Find the length of the chord of the larger circle which touches the smaller circle.
✅ Answer & Solution
Let the chord AB of the larger circle touch the smaller circle at point P. Since AB is tangent to the smaller circle at P, $OP \perp AB$, and P is the midpoint of AB. In right triangle OPA: $OA^2 = OP^2+PA^2$. $5^2 = 4^2+PA^2$. $PA^2 = 25-16=9 \Rightarrow PA=3$ cm. Chord $AB = 2 \times PA = 6$ cm.
