SOLUTION: In triangle ABC , measurement of angle B = 60 degree. Prove that m( AC)^2=(mAB)^2+(mBC)^2-(mAB).(mCB)

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Question 1067188: In triangle ABC , measurement of angle B = 60 degree. Prove that
m( AC)^2=(mAB)^2+(mBC)^2-(mAB).(mCB)

Answer by ikleyn(52824) About Me  (Show Source):
You can put this solution on YOUR website!
.
Use the "Cosines Law" for triangles.

Also use the fact that cos(60 degs) = 1%2F2.

Nothing else.