LetthetwopointsbeP(0,0)andQ(36,15)Now,PQ=√(x2−x1)2+(y2−y1)2=√(36−0)2(15−0)2=√(36)2+(15)2=√1296+225=√1521=39.Now,ItisgiventhatBislocated36kmeastand15kmnorthoftownA.LetustakeAasorigin.Now,AB=√(36−0)2+(15−0)2=√12596+225=√1521=39.Hence,thedistancebetweenthetwotownsis39km.