Aburro is standing near a cactus. the burro is 58 in. tall. his shadow is 4 ft long. the shadow of the cactus is 8 ft long. what's the height of the cactus?

To find the height of the cactus, make a ratio.

58 inches divided by 4 feet equals x inches divided by 8 feet.

58/4 = x/8

14.5 = x/8

116 = x

The height of the cactus is 116 inches.

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+

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