Find polar coordinates with for the following Cartesian coordinates:

$(a)If(x,y)=(16,-9)$ then

$,$

$,$

$(b)If(x,y)=(10,-6)$ then

$sqrt(136)$

$,$

$(c)If(x,y)=(-3,0)$ then $(r,)=$

$,$

$,$

$(d)If(x,y)=(0,7)$ then

$.$