Hi, there-- THE PROBLEM: a) If (x, y) = (20,-4) then (r, theta)= A SOLUTION: We use these conversions to translate from Cartesian to Polar Coordinates. Note the quadrant in which (x,y) lies in order to select the correct angle (between -pi/2 and pi/2). r = sqrt(x^2 + y^2) where r is distance from origin to the point x is value of the x-coordinate y is value of the y-coordinate θ = arctan(y/x) where θ = angle relative to the zero axis (in degrees) Given (x, y) = (20,-4) then r = sqrt(x^2 + y^2) r = sqrt((20)^2 + (-4)^2) r = sqrt(400 + 16) r = sqrt(416) r = 2*sqrt(104) ≈ 20.396 θ = arctan(y/x) θ = arctan((-4)/(20)) θ = arctan(-0.2) θ ≈ -0.197 The polar coordinates (in radians) are approximately (20.396, -0.197). Try the rest on your own. Hope this helps! Feel free to email if you have any questions or want to check your answers. Good luck with your math, Mrs. F math.in.the.vortex@gmail.com