Answer
0.30 m
Work Step by Step
x component of $\vec{d_{3}}= |\vec{d_{3}}|\cos\theta$
where $\theta$ is the angle that vector makes with the positive direction of x-axis.
Therefore x component of $\vec{d_{3}}$$= 0.60\,m\times\cos 60^{\circ}=0.30\,m$
