The diameter and a chord of circle have a common end-point. If the length of the diameter is 20 cm and the length of the chord is 12 cm, how far is the chord from the center of the circle?

We have,

   

as the diameter and

   

as the chord.

Now, draw 

   

Since

   

 and hence it bisects

   

   

is the centre of the circle.

Therefore,

   

Now, in right

   

   

[By Pythagoras Theorem]

   

   

So,

   

Therefore, the chord is at a distance of 8 cm from the centre of the circle.