Now circles…. can this get any worse?

The perpendicular from the centre of a circle to a chord, bisects the chord 

so

PR=10

Then using pythagoras' theorum

$$\\12^2=10^2+x^2\\\\
144=100+x^2\\\\
44=x^2\\\\
x=\sqrt{44}\\\\
x=\sqrt4 \times \sqrt{11}\\\\
x= 2\sqrt{11} \;\;units\\
x= 2\sqrt{11} \;\;units\\
x=6.6332496\;units\\
x=6.63 \;\mbox{units to 2 decimal places}$$

Thanks Alan.

Look carefully at the information you have in the diagram.  With O as the centre of the circle and a right-angle at R, then length PR is half of length PQ, so PR is 10.  This means you have a right-angled triangle with hypotenuse of length 12, one side of length 10 and one of length x.  From Pythagoras we know that:

x² + 10² = 12².   Can you take it from there?

Ok, no need to - Melody's already done it!!  Apart from expressing the answer as a decimal rounded to two places.

You know Rose those first two joint lines on the top of the circle seemed to me as if they were someones mustaches when i saw them first!

Yes they do a bit Rosala.

they'd match lots if the lines might have been a lil more thicker!

If you know what regular show is then it looks like the guy named pops lol

zegroes, that was so random.... hahaha

It wasnt random if you watched regular show you would know.

Alrighty whatever you say 

Zegroes, im happy atleast theres anyone in this world from whom u can win!but take care peole r very clever though!