Students taking CSM test - Polar Coorindates

There is a question for polar coordinates on the exam, however that is not in our curriculum. Here are 2 videos for polar coordinates.  I like the one from ck12 the best.  It uses a context of a dartboard to explain the polar coordinates.    

https://www.ck12.org/c/trigonometry/plots-of-polar-coordinates/lesson/Plots-of-Polar-Coordinates-TRIG/?referrer=concept_details

https://www.khanacademy.org/math/precalculus/imaginary-and-complex-numbers/polar-form-of-complex-numbers/v/polar-form-complex-number?modal=1