So I'm thinking we use the point P and the origin O Which would be (0,0,0) subtract or add them (not sure) and somehow find the OE. Any help?
Notice that we can write (5, 2, 4) as the linear combination
1(5, 0, 0) + 1(0, 2 , 0) + 1(0, 0, 4) = vector (OE) +vector( ED) + vector (DP)
So......the length of OE = 5
+956 
