Estimating and Costing
The correct Prismoidal formula for volume is

D [first area + last area + Ʃ Even area + 2 Ʃ odd areas]
D/3 [first area + last area + 4 Ʃ Even area + 2 Ʃ odd areas]
D/3 [first area + last area + 2 Ʃ Even area + 4 Ʃ odd areas]
D/6 [first area + last area + 2 ∑ Even area + 4 ∑ odd areas]

ANSWER DOWNLOAD EXAMIANS APP

Estimating and Costing
The assumption on which the trapezoidal formula for volumes is based, is

The end sections are parallel planes
The volume of the Prismoidal is over-estimated and hence a Prismoidal correction is applied
All listed here
The mid-area of a pyramid is half the average area of the ends

ANSWER DOWNLOAD EXAMIANS APP