Perpendicular vectors

burgerandcheese

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Jul 2, 2018
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EDIT: Nevermind it's solved. Please delete my post.



Question: A pyramid of height 3 units stands symmetrically on a rectangular base ABCD with AB= 2 units and BC= 4 units. Find the angle between two adjacent slanting faces.

12302
O is the origin

The given solution was first find the vectors p and q which are the normal to the faces VAB and VBC respectively to get the angle between them by using p.q = |p||q|cos(θ)

What the book did was: if MV = <-2, 0, 3> then p = <3, 0 , 2> but I don't know how they got that.
What I thought was if p and MV are perpendicular to each other then p.MV = 0
So why isn't p = <1/2, 0, 1/3> since if you multiply that with MV = <-2, 0, 3> you get 0

12303

Thank you in advance
 
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