Disgusting A-Level Maths Questions - Circle Geometry

Disgusting A-Level Maths Questions - Circles
Tangents to circles, circle theorems, chords, perpendicular bisectors, Pythagoras... All that good stuff will be tested in today's disgusting A-Level maths question!
It's not a massive question, but the difficulty lies in reading it and effectively taking all of the information in, crucial to exam technique. Question taken from AITutor: aitutor.co.uk

[@paulm884]

Supprisingly simple when the graph is drawn, if they had drawn the information they gave you then this would be only one mark if that.

[@T9RPZz]

Love these videos mate definitely deserve loads more subscribers

[@elaethmyersmccraw]

but how do we know that we are allowed to leave it as r? was there more info in the question or is it just a convention of the exam board. i feel like normally you can only use the predefined variables.

[@Ojisgay]

Maths question with no numbers💀

[@gabdass2146]

your videos are awesome =)

[@gracechan4775]

Does the word required mean we don't need to account for if S were on the opposite side of the circle?

[@Ojisgay]

Then it wouldn’t be line cms it would be scm I think

[@regularman4063]

Hi,
I might be making an obvious error, but can't you write the answer as r+y-x. Or is there a reason why u cannot remove the square root.
Thanks

[@missachin5054]

Square roots could be + or -

[@gangang724]

Basically if you sqare root it from the start, it would either be - or +
Because you are finding a length, it will have to be positive