Let P(0,7,10),Q(−1,6,6) and R(−4,9,6) be the vertices of a triangle Here, PQ=1+1+16​=32​QR=9+9+0​=32​PR=16+4+16​=6 Now, PQ2+QR2=(32​)2+(32​)2=36=(PR)2 Therefore,ΔPQR is a right angled triangle at Q. Also, OQ=QR. Hence, ΔPQR is a right angled isosceles triangle.