Find the magnitude and direction angle of the vector a given below. Express your answer to one decimal place.

$a = 12i - 18j$

For the given vector, calculate its magnitude and direction angle relative to the positive $x$-axis. Express your answer to the nearest tenth, if required.

$〈-17,-29〉$

For the given vector, calculate its magnitude and direction angle. Express your answer to the nearest tenth, if required.

$〈28\sqrt3,-28\sqrt3〉$