13. Franz's Bakery is getting more and
more orders for blackberry pies. The
bakers made 4 blackberry pies in
October, 5 blackberry pies in
November, 7 blackberry pies in
December, 10 blackberry pies in
January, and 14 blackberry pies in
February. If this pattern continues,
how many blackberry pies will the
bakery make in March?
A. 19
B. 24
C. 15
D. 21

i dont know itanswer:

step-by-step explanation:

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