How do you convert #(−2, −9)# into polar form? Precalculus Polar Coordinates Converting Equations from Polar to Rectangular 1 Answer Vinícius Ferraz Feb 6, 2017 #sqrt 85 [cos (pi + arctan 4.5) + i sin (pi + arctan 4.5)]# Explanation: #-2 = r cos t, -9 = r sin t# #tan t = 9/2# #t = pi + arctan 4.5# Where we add #pi# because our point is at 3rd quadrant. #2^2 + 9^2 = r^2 = 85# 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 1602 views around the world You can reuse this answer Creative Commons License