Angle of a trapezium

Geometry Level 5

$ABCD$ is a trapezium with $AD \parallel BC$ and $AB = AD$ . $0^\circ < \theta < 180^\circ$ is an angle such that $\angle BAC = \theta$ , $\angle CAD = 3 \theta$ and $\angle ACD = 5 \theta$ . What is the measure (in degrees) of $\theta$ ?

Details and assumptions

A trapezium has a pair of parallel sides.