Chapter 17 - Line and Surface Integrals - 17.1 Vector Fields - Preliminary Questions - Page 918: 3

$\langle 0,-z,y\rangle $ (other answers are possible.)

The position vector $\langle x,y,z\rangle $ is orthogonal to the vector $\langle -z,0,x\rangle $, since $$\langle x,y,z\rangle \cdot \langle -z,0,x\rangle = -zx+zx=0.$$ Another vector which is orthogonal to the position vector $\langle x,y,z\rangle $ is $\langle 0,-z,y\rangle $, since $$\langle x,y,z\rangle \cdot \langle 0,-z,y\rangle = -zy+zy=0.$$