john458776
New member
- Joined
- May 15, 2021
- Messages
- 48
[imath]AB=<-5,3,-3>[/imath]
[imath]BC=<8,1,1>[/imath]
[imath]AB.BC=(-5)(8)+(3)(1)+(-3)(1)=-40[/imath]
[imath]||AB||=sqrt(48)[/imath]
[imath]||BC||=sqrt(66)[/imath]
[imath]tetha=138,66°[/imath]
I think the approach I use is correct but now I was thinking if the same problem would say I should find the size of angle BCA.
Then first I should find BC and CA, then I proceed with other steps, is that right or the is something im missing here ?