How do you convert #r = 4cos(theta)# into rectangular form? Trigonometry The Polar System Converting Between Systems 1 Answer Bdub Mar 8, 2016 #(x-2)^2 +y^2=4# Explanation: #r=4costheta# #r^2=4rcos theta#-> multiply both sides by r #x^2+y^2 = 4x#-> substitute in #x^2+y^2# for # r^2# and #x# for #rcos theta# #x^2-4x+y^2=0#-> combine like terms #(x-2)^2+y^2=4#->complete the square 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 21713 views around the world You can reuse this answer Creative Commons License