How do you change the polar equation #r=3costheta# into rectangular form? Trigonometry The Polar System Converting Between Systems 1 Answer sjc Oct 27, 2016 #x^2+y^2=3x# Explanation: for polars/rectangular #x^2+y^2=r^2# #x=rcostheta# #y=rsintheta# #r=3costheta#-----(1) #xx# (1) by #r# #r^2=3rcostheta# #x^2+y^2=3x# Answer link Related questions How do you convert rectangular coordinates to polar coordinates? When is it easier to use the polar form of an equation or a rectangular form of an equation? How do you write #r = 4 \cos \theta # into rectangular form? What is the rectangular form of #r = 3 \csc \theta #? What is the polar form of # x^2 + y^2 = 2x#? How do you convert #r \sin^2 \theta =3 \cos \theta# into rectangular form? How do you convert from 300 degrees to radians? How do you convert the polar equation #10 sin(θ)# to the rectangular form? How do you convert the rectangular equation to polar form x=4? How do you find the cartesian graph of #r cos(θ) = 9#? See all questions in Converting Between Systems Impact of this question 1153 views around the world You can reuse this answer Creative Commons License