Item 8 Select the cone(s) that are similar to a cone with a height of 9 meters and a radius of 3 meters.
cone with a height of 15 meters and a radius of 6 meters
cone with a height of 12 meters and a radius of 4 meters
cone with a height of 6 meters and a radius of 3 meters
cone with a height of 3 meters and a radius of 1 meter

pls ask

geometry: triangles

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lessons

answers archive

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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