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VCE Stuff => VCE Mathematics => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Specialist Mathematics => Topic started by: director on April 26, 2014, 03:58:10 pm

Title: i thought i was right :(
Post by: director on April 26, 2014, 03:58:10 pm

P is (-1,3) Q is (12, 4) R is the midpoint of PQ
Find OR and show R is equidistant from the three vertices of POQ

if OP = -i+3j
OQ = 12i +4j
PQ = PO +OQ = i +3j + 12i +4j = 13i + j
isn't or just 1/2 of PQ therefore OR = (13/2)i +(1/2)j?

if i do that and i find te magnitude of PR and QR they arent the same so they aren't equidistant which is not what the question is saying
i'm so lost help!!
thank you

Title: Re: i thought i was right :(
Post by: hobbitle on April 26, 2014, 04:05:52 pm

Looks like someone is making a new account for each post they make, this is about the sixth or seventh thread in the last few days that has been started in Spec Maths, each user with only one post asking questions with a similar theme?

Title: Re: i thought i was right :(
Post by: keltingmeith on April 26, 2014, 04:07:25 pm

Close - PR = (1/2) PQ. Just one step away to finding OR!

OR = OP + PR = -i + 3j + (13/2)i + (1/2)j

Using this, assuming the question is right, you should find that |OR| = |PR| = |RQ|