# More of those dreaded circles

• Dec 29th 2007, 07:17 AM
Geometor
Yup, another circle question and it seems as though the question list is never-ending. Well, I'm stuck. Again... but here goes
TA and TB are tangents to the circle. C is a point on the circle. P, Q and R are the feet of the perpendicular from C to the three sides of triangle ABT
a) Name three groups of concyclic points (got this)
b) hence show that angle CRQ = angle CQP and angle CQR = angle CQP
c) if QC = 9cm and PC = 10cm, find CR.

http://img168.imageshack.us/img168/6955/43696800si4.png

Any help appreciated!
• Dec 29th 2007, 07:46 AM
Isomorphism
Quote:

Originally Posted by Geometor
Yup, another circle question and it seems as though the question list is never-ending. Well, I'm stuck. Again... but here goes:
a) Name three groups of concyclic points (got this)
b) hence show that angle CRQ = angle CQP and angle CQR = angle CQP
c) if QC = 9cm and PC = 10cm, find CR.

http://img205.imageshack.us/img205/900/44316023lh6.png

Any help appreciated!

Yikes! Where is C?
• Dec 29th 2007, 07:56 AM
Geometor
thank you for submitting that error
the correct picture has now been put in
• Dec 29th 2007, 08:05 AM
Isomorphism
Quote:

Originally Posted by Geometor
thank you for submitting that error
the correct picture has now been put in

You are welcome :D

You have not mentioned how you have chosen C. Is it >any< point inside the triangle. Is it some special point?
• Dec 29th 2007, 08:23 AM
Geometor
aha :D I've snuck in the description too