Math wizards. Need help grasping Volume in a 3d space. Will rep off charge.

[EyesCold]

Ok, so say at my work i have to get the volume dug out for a new 2" pipeline being laid out. I have to figure out how much material(mud) is being displaced for the new pipeline. Got a picture to show you what i mean. Poorly.

i forgot to add the water depth but it is averaging about 2.5' if that helps. i know the formula for volume and can use the formula for square objects but this angled objects are fuking my mind up. that is all i need to grasp to keep my job and i can't do it.

hope someone can make sense of this jajajajajajaaja
http://img41.imageshack.us/img41/6553/volumel.jpg

[LeetSupaHaxor]

You must first find the average of 5' and 2', which is (5+2)/2 = 3,5'.
then multiply it by the depth of water, which is 2,5':
3,5*2,5 = 8.75' (this is the area of the first figure)
So, now to calculate the volume, we must multiply it by another dimension, length, which is shown in ur second picture, and is 428,23'. So, calculating:
8,75*428,23= 3747

[EyesCold]

that is perfect man. how would that work with multiple depths of water along that distance?

[EyesCold]

let me guess.. you take the average of the water depths if multiple water depths?\

[baelish]

let me guess.. you take the average of the water depths if multiple water depths?\

http://i52.tinypic.com/2wf8tuq.jpg

For the above pictures, each section represents a different water depth.

That would only work if each section of water depth is equal in size, like in the top diagram.

If the sections of different water depths are not equal in size, like the bottom diagram, then you have to calculate volume for each section and then add them all up.

[MiKey4]

What do you mean "water depth"? Where is water in this whole thing?

Do you mean the height of the trapezoid? How does it simply change from one height to another? And why?


Anyway, to keep things simple just work out the volumes of each section separately and add them up.