Under shah abbas, the safavid dynasty
a.
reached the high point of its glory.
b.
rapidly declined until it was too weak to fight off its many enemies.
c.
suffered an invasion by moroccan peoples, who captured the capital of isfahan.
d.
witnessed a relaxation of traditional religious beliefs.

the reason why your question keeps getting deleted because this is not a school related question : )

i will answer your question though.

i never tried church's

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