Mary initially puts $2 into a piggy bank. She continues to save money such that the amount of money in the piggy bank doubles each
week.
Which of the following graphs shows the amount of money, y, in dollars, in Mary's piggy bank after x weeks?

idk

step-by-step explanation:

215.92 dollars is the answer

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