Someoneit would take 38 minutes to fall through a (hypothetical) hole from one end of the earth to the other. until recently, it was thought to be 42 minutes. what is the percent change in the "hypothetical" time it

geometry: triangles

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call the larger triangle abc

then the smaller triangle cde is similar to abc (all angles are equal, aaa).  

ab is the side that is 36, and we wish to find de, the side corresponding to ab

area_cde = area_abc - area_cde --> area_abc / area_cde = 2

let x=length of de

ratio of areas = (ratio of sides)^2

+2+=+%2836%2fx%29%5e2+

+2+=+1296%2fx%5e2+

++x%5e2+=+1296%2f2+=+648+

25.45584

there are no multiple choices

time is equal to distance over rate so

t = d/r

need a little bit more information for the second question.