Question

If the radii of two concentric circles are 5cm and 13cm, then the length of the chord of one circle which is tangent to the other circle is:

Answer 1

do not considered the picture is not proper circle only Kis Kis cheez ki

Answer 2

The radii of two concentric circles is 24 cm.

Step-by-step explanation:

Given:

We have AD=13 cm [Radius of bigger circle]

CD=5 cm [Radius of smaller circle

As line joining point of contact of tangent to centre of circle is perpendicular to tangent.

Hence CD⊥ AB.

Now perpendicular from centre of circle to the chord bisects the chord. Hence DC bisects chord AB of bigger circle.

AB=2 AC or AC=BC

Now in right angled triangle ACD, we have

$AC^2-CD^2=AD^2$     [Pythagoras Theorem]

$AC^2=AD^2-CD^2$

$AC^2=13^2-5^2$

$AC^2=169-25$

$AC^2=144$

$AC=\sqrt{144}$

AC=12 cm

Therefore AB=2AC

                 AB=$2\times12$

                 AB=24 cm.