Mark paid $2 94 in sales tax on an item that cost $42.00 before tax. at that rate, how much would he pay in sales tax for an item that costs $58.00 before tax?

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

r = 78539458390583095803458309458039485093485 or just 3

step-by-step explanation: