12. Find the chord length

1. Let $O$ be the centre of the circle and $AB$ be its chord. A line from $O$ cuts the chord $AB$ at $C$ such that $\angle OCB$ $= 90^{\circ}$. If $AC$ $=$ 18 $cm$. Find the length of the chord.

 

Answer:

 

The length of the chord $AB$ is  $cm$.

 

 

2. If the radius of the circle is 5 $cm$ and the perpendicular distance from the centre to the chord is 4 $cm$, then find the length of the chord.

 

Answer:

 

The length of the chord is  $cm$.