Let a=2i+3j+4k=OA b=3i+4j+2k=OB and c=4i+2j+3k=OC AB=OB−OA=i+j−2k BC=OC−OB=i−2j+k and CA=OA−OC=−2i+j+k Now, AB=√1+1+4=√6 BC=√1+4+1=√6 and CA=√4+1+1=√6 Since, the length of all three sides are equal. So, the triangle is an equilateral triangle