Determine if the graph is symmetric about the x-axis, the y-axis, or the origin.
r = -5 - 5 cos θ

A. Origin only
B. x-axis only
C. y-axis only
D. No symmetry

1. credits

2. dual - aspect

hope i : )

we have three similar triangles, because each has a right angle and shares an angle.   let's write the angles in order: opposite to short leg, long leg, hypotenuse.

cab similar to bad similar to cbd

or as ratios,

ca: ab: cb = ba: ad: bd = cb: bd: cd

we also know

ac = ad + cd

(ad+cd): ab: cb = ba: ad: bd = cb: bd: cd

(ad+cd)/cb=cb/cd

we have cb=6, ad=5 and seek x=cd.

we reject the negative root and conclude x=4

answer: 4

ratio is 2 : 9

the answer is three

13.5 : 3