Answer:
a) 
b) 
Step-by-step explanation:
Polar coordinates are represented as:
, where 'r' is the length (or magnitude) of the line, and '
' is the angle measured from the positive x-axis.
in our case:

to covert the polar to cartesian:


we can plug in our values:


the Cartesian coordinates are:


(b) to convert (x,y) = (6.06,-3.5)
we'll use the pythagoras theorem to find 'r'



the angle can be found by:




to convert radians to degrees:

writing in polar coordinates:

X+5+2x-2+90=180. combine like terms and solve like a normal algebra problem to find x. if you need to find the answer for a certain angle, plug in the value you got for x into one of the angle equations
As the exterior angles always add up to 360, you can find the number of sides by dividing 360 by the measure of your exterior angle, 30. This gives you 360/30=12, meaning your polygon has 12 sides.