Question

Two concentric circles are of the radii 5cm and 3cm. Find the length of the cord of the larger circle which touches the smaller circle.​

Answer 1

$\huge \mathscr{\orange {\underline{\pink{\underline {Answer:-}}}}}$

Let O be the centre of the concentric circle of radii 5 cm and 3 cm respectively. Let AB be a chord of the larger circle touching the smaller circle at P. 

Then,

AP = PB and OP⊥AB

Applying Pythagoras theorem in △OPA,

We have,

OA² = OP² + AP²

⇒25 = 9 + AP²

⇒ AP² = 16

⇒ AP = 4 cm

∴AB = 2AP = 8 cm