Solve the Equation for Solutions Over the Interval [0 $[ 0,2 \pi )$

Solve the equation for solutions over the interval [0, $[ 0,2 \pi )$ ) . Write solutions as exact values or to four decimal places, as
appropriate.
-Let $( a , b )$ and (c, d) be two points in the first quadrant, and let $\theta$ be the angle between the line segme connecting $( a , b )$ with the origin and the line segment connecting (c, d) with the origin. It can be shor $\cos \theta = \frac { a c + b d } { \sqrt { \left( a ^ { 2 } + b ^ { 2 } \right) \left( c ^ { 2 } + d ^ { 2 } \right) } }$
Find $\theta$ if $a = 4 , b = 2 , c = 8$ , and $d = 6$ . Give your answer in degrees rounded to the nearest hundredth.

A) $44.31 ^ { \circ }$
B) $74.44 ^ { \circ }$
C) $63.43 ^ { \circ }$
D) $10.30 ^ { \circ }$