How do you convert r cos(θ) = 9 into cartesian form? Precalculus Polar Coordinates Converting Equations from Polar to Rectangular 1 Answer Bdub Sep 12, 2017 see below Explanation: use the formula x=rcos theta That is, rcos theta = 9 :. x=9 Answer link Related questions What is the polar equation of a horizontal line? What is the polar equation for x^2+y^2=9? How do I graph a polar equation? How do I find the polar equation for y = 5? What is a polar equation? How do I find the polar equation for x^2+y^2=7y? How do I convert the polar equation r=10 to its Cartesian equivalent? How do I convert the polar equation r=10 sin theta to its Cartesian equivalent? How do you convert polar equations to rectangular equations? How do you convert r=6cosθ into a cartesian equation? See all questions in Converting Equations from Polar to Rectangular Impact of this question 4415 views around the world You can reuse this answer Creative Commons License