I really dont know to how to get the values?!!?!
i understand solving 2d vectors
But when the image is given i just cant.
how should i proceed!
cie as p1,nov 2007 
please,explain
Thank you.
10)i) PR= 2i + 2j +2k
PQ= -2i+2j+4k
ii) QPR is PQ and PR. When they say scalar you have to do this a.b(a multiplied by b) so PQ.PR = 2(-2) + 2(2) + 2(4) = -4 + 4 +8 =8
Now to get an angle you should know this formula : Cos (theta) = a.b/ |a|x|b|
we got a.b, so now |a| and |b|
|PR| = square root of (2^2 + 2^2 +2^2) = square root of 12
|PQ|= square root of (-2^2 + 2^2 + 4^2) = square root of 24
cos QPR = 8 / square root of 12 x square root of 24
iii) to get the perimeter you will need to get the position vector of PR, PQ and QR, make them under square root each and then add. Now you already got for PR and PQ in part i) so only QR is missing which is 4i +0j - 2k.
square root each of them and add them to get the perimeter.
Nothing is there, all you need to do is look at the image and match lines. Just look carefully with full concentration.
@Nid, how do you write the square roots, brackets, theta, etc?
