Answer
a) $-21.2\;\hat k$
b) $24\;\hat k$
Work Step by Step
a) We can use the right-hand rule to find the direction of the resultant vector but we also can use the direction of the angle which is negative here since the angle from $\vec A$ to $\vec B$ is clockwise.
$$\vec A\times \vec B=AB\sin(-45)^\circ\;\hat k$$
We assume that the two vectors are in the $x$-$y$ plane.
$$\vec A\times \vec B=-AB\sin45^\circ\;\hat k$$
where $\hat k$ is the $z$-direction and since it is negative, then its direction is out of the page toward you. We can test that also by using the the right-hand rule.
$$\vec A\times \vec B=-(6)(5)\sin45^\circ=\color{red}{\bf -21.2}\;\hat k$$
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b) The angle from $\vec C$ to $\vec D$ is counterclockwise, so it is a negative direction and the resultant vector is perpendicular to the page out toward you. In other words, it is in the positive $ z$-direction.
$$\vec C\times \vec D=CD\sin90^\circ\;\hat k$$
$$\vec C\times \vec D=(6)(4)\sin90^\circ=\color{red}{\bf 24}\;\hat k$$