Question

If radii of two concentric circles are 6cm and 8cm, then the length of the chord of outer circle which is tangent to the inner circle is:

Answer 1

We know that tangent and radius are perpendicular at the point of contact.

Also, the perpendicular from center to any chord, bisects the chord.

For the larger circle, we can find the half length of the chord using Pythagoras' theorem.

It is found to be : 

102 − 62​ = 8cm

So the length of the required chord is :

2 × 8 = 16cm.

So 16cm is the right answer.