A triangular pyramid has an equilateral triangle for the base with a base of 3m and a height of 2m. The height of the pyramid is 18 meters. The slant height is 3.5 m. What is the lateral area of the pyramid?
A.15.75 meters
B.162 meters
C.81 meters
D.31.5 meters

B

Step-by-step explanation:

I did the problem

c

step-by-step explanation:

because of the levels

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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