3. Vectors

Vector ${\vec{V}}_1$ points along the $z$ axis and has magnitude $V_1=75$. Vector ${\vec{V}}_2$ lies in the $xz$ plane, has magnitude $V_2=48$, and makes a $-{48}^{\circ }$ angle with the $x$ axis (points below the $x$ axis). What is the scalar product ${\vec{V}}_1\cdot {\vec{V}}_2$?