A)
A1-upper base
A2-medsection
A3-lower base
Formula of volume of prismatoid:
V=6L⋅(A1+4⋅A2+A3)
V=6100⋅(90+4⋅120+210)=13000m3
Answer: volume of prismatoid: 13000m3
B)
u-upper base
l-lower bas
a-altitude
m-midsection edge
A-area of midsection
cotα=u/2x=m/2x+a/2=l/2x+a
lx=ux+ua
x=l−uua=20−1212⋅14=21cm
m=xu(x+a/2)=2112(21+14/2)=16cm
A=m2=162=256cm2
Answer: midsection is 256cm2
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