Answer
Direction = negative z axis $(-k)$
Work Step by Step
To solve this we use unit vectors of the direction to solve the equation.
$d1 $ is in the negative y direction $( -j) = ( 0i -1j + 0k)$
$d2$ is in the positive x direction $( i ) = ( 1i + 0j + 0k)$
$d2 \times d1 = (d2_yd1_z - d2_zd1_y)i +(d2_zd1_x - d2_xd1_z)j + (d2_xd1_y - d2_yd1_x)k$
$((0\times 0)-(0\times-1))i + ((0\times0)-(1\times0))j+((1\times-1)-(0\times0))k = 0i +0j-1k$
Direction = negative z axis $(-k)$
