Can you please explain how to get θ=5.560 when r=0 for the equation r=3-4cosθ?

Question

Analyzing the graph for r=3-4cosθ

Type: Limacon with inner loop

Symmetry: Polar axis

Max r=7 θ=pi

r=0 θ=.723, 5.560

I understand that θ=pi when the max value of r is 7, and I understand θ=.723 when r=0 but I don't understand how θ=5.560 when r=0. I got that θ=.723 when r=0 by

setting the equation to 0=3-4cosθ

subtracting 3 and dividing both sides by -4 3/4=cosθ

then taking the inverse cosine of each side cos^-1(3/4)=cos^-1(cosθ)

to get θ-.723

Answer 1

0 = 3 - 4 cos θ

-3 = -4 cos θ

0.75 = cos θ

41.4196 ≈ θ