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A regular square pyramid has a base whose area is 25 sq. In. A section parallel to the base and 3.18 in above it has an area of 4 sq. In. Find the ratio of the volume tp the frustum tp the volume of the pyramid

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Given:
H = 3.18 in
B = 25 in^2
b = 4 in^2

Req'd: Vfrustum/Vpyramid

Using ratio & proportion..
HP = 3.18 + hp

HP/hp = 5/2
3.18 + hp / hp = 5/2
(3.18 + hp) 2 = 5hp
6.36 + 2hp = 5hp
6.36 = 3hp
2.12 = hp

So, HP = 3.18 + 2.12
HP = 5.3

Vpyramid = BH/3
BH/3 = (25*5.3) / 3
Vpyramid = 44.1667 in^3

Vfrustum = H/3 [B + b + sqrt of Bb]
= 3.18in/3 [25in^2 + 4in^2 + sqrt of 100in^4]
= 3.18in/3 [ 29in^2 + 10in^2]
= 3.18in/3 (39in^2)
Vfrustum = 41.34 in^3

Req'd: Vfrustum / Vpyramid
41.34 in^3 / 44.1667 in^3

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