[질문] 한점에서직선까지의거리공식알려주세요

직선을ax+by+c=0,----(1)그리고임의의한점을P(x1,y1)라고놓겠습니다.점P를지나직선에수직인직선의방정식은(y-y1)=b/a*(x-x1)이고,이를정리하면b(x-x1)-a(y-y1)=0