Turn on thread page Beta
    • Thread Starter
    Offline

    9
    ReputationRep:
    A circle with centre C has equation x^2 + y^2 +8x - 12y = 12
    11 (a)
    Find the coordinates of C and the radius of the circle.

    i got 8 for radius and (-4,6) for C

    11 (b)
    The points P and Q lie on the circle.
    The origin is the midpoint of the chord PQ.
    Show that PQ has length n√3 , where n is an integer.

    im stuck on how to answer part B
    drew out the circle on the graph but im still stuck
    • Community Assistant
    Online

    20
    ReputationRep:
    Community Assistant
    (Original post by Chez 01)
    ...
    If the centre is R, then the segment RO is a perpendicular bisector to PQ. Furthermore, you can actually find the length of the segment RO. Also you know that the length of the segment RP is the radius. Note the right-angled triangle ROP and deduce the length of PO
    • Thread Starter
    Offline

    9
    ReputationRep:
    (Original post by RDKGames)
    If the centre is R, then the segment RO is a perpendicular bisector to PQ. Furthermore, you can actually find the length of the segment RO. Also you know that the length of the segment RP is the radius. Note the right-angled triangle ROP and deduce the length of PO
    i dont understand
    • Community Assistant
    Online

    20
    ReputationRep:
    Community Assistant
    (Original post by Chez 01)
    i dont understand
    You can find the lengths of the purple and black dashed lines, hence determine half of the orange one through Pythagoras.

    • Thread Starter
    Offline

    9
    ReputationRep:
    thank you for the graph, i drew my circle graph wrong. l will attempt the question again
    Posted on the TSR App. Download from Apple or Google Play
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: January 21, 2018

1,090

students online now

800,000+

Exam discussions

Find your exam discussion here

Poll
Should predicted grades be removed from the uni application process
Useful resources

Make your revision easier

Maths

Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

Equations

How to use LaTex

Writing equations the easy way

Student revising

Study habits of A* students

Top tips from students who have already aced their exams

Study Planner

Create your own Study Planner

Never miss a deadline again

Polling station sign

Thinking about a maths degree?

Chat with other maths applicants

Can you help? Study help unanswered threads

Groups associated with this forum:

View associated groups

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.