Justin is pouring a concrete walkway around his grandmother's rectangular garden. he wants the walkway to be 3 feet wide all the way around. if his grandmother's garden is 25 feet by 43 feet, what is the area of the top of the walkway

step-by-step explanation:

in which figure is point g a centroid

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