An inverted square pyramid has a height equal to 8m and a top egde equal to 3m. Initially, it contains water to a depth of 5m.

Answer 1

Is there a question ?

I asssume you want the volume of water.

Sketch a cross-section.
let the width of the water level be x
by ratios:

x/3 = 5/8
8x=15
x=15/8

volume = (1/3)base x height
= (1/3)(15/8)^2 (5)
= appr 5.86 m^3

check my arithmetic