In Support Vector Machine, why is the distance from the origin to the decision boundary b / ||w||

Question

In the picture of SVM from Wikipedia, at the lower left corner - pointed by the red arrow, the distance from the (0,0) to the decision boundary is b / ||w||. Why is that? Thanks.

Answer 1

I believe this may explain it. Note: it seems that the picture from Wikipedia should more correctly show a dot product instead of a star I think. I hope this helps.