View Full Version : How the **** do i figure out the volume of a triangle

I Like Waffle
02-12-2009, 03:34 PM
Obviously i fail at math but im trying to figure out the volume of this triangle-ish box im working on designing. I think im going in the wrong direction here but i need about 7 cubes net, and a box no taller than 15 inches, has to be slant face as the subs are 15.5 inches wide. Im gonna attempt to do this myself but im having trouble planning everything out before i get the materials

Heres my max specs. I could go bigger but i wanna leave a little airspace around the box too.

15.5 inches tall
18 inches deep
55 inches wide (this is pushing the limits of my trunk, i have 60 inches of width in total, at the trunk opening)

heres what i got so far


02-12-2009, 03:37 PM
add top and bottom depth and divide by 2, thats the length of the depth

02-12-2009, 03:37 PM
separate that into a triangle and a rectangle. for the triangle its (1/2)(base)(height)(length) and then for the rectangle its just (H)(W)(L)

02-12-2009, 03:38 PM
Measure the depth and the 1/2 the height use that as your "D" in ( L * W * D/1728) and there is your answer

02-12-2009, 03:39 PM
If all else fails, build it, and fill it with packing materials.

Then empty the packing materials into a square or rectangular container.

Measure said packing materials.

02-12-2009, 03:39 PM
use geometry skills learned in 10th grade

john denver
02-12-2009, 03:41 PM
im getting just under 7 like 6.8 assuming those are outer dimensions using 3/4"

02-12-2009, 03:42 PM
You are a ******* retarded :fyi:

02-12-2009, 03:42 PM
A triangle is two dimensional; thus no volume.
A prizm is the word you are looking for.

I Like Waffle
02-12-2009, 03:49 PM
that will get me about 4 1/2 cubes before displacement. Im gonna have to figure out something else :crap:

02-12-2009, 03:53 PM
Area of that triangle = (1/2)(12)(14) + (4)(14)

Multiply it by how many inches you want to extrude it and you'll get its volume in cubic inches.

Divide it by 12*12*12 to get cubic feet.

02-12-2009, 03:55 PM
there is a calculator for that specific box shape on BCAE.

02-12-2009, 04:07 PM

half way down

02-12-2009, 04:07 PM
2.982 cubic feet?

02-12-2009, 04:20 PM
Just seperate it into two pieces...the rectangle on the right and the triangle on the left....then simply find the area of the rectangle and then just (height x width = y....then y/2 will get you the area of the triangle)...then add that to the rectangle's area and multiply it by your depth of the object for your volume :)

I Like Waffle
02-12-2009, 05:18 PM
Farmer that site you linked is great. With a little modification to my design i can get about 6.2 cubes which will be perfect for what i need. Now off to home depot to buy mdf :cool:

I Like Waffle
02-12-2009, 09:28 PM
Went to home depot and got all the stuff i need to finish it. Some titebond II, clamps, screws etc. Got all the wood cut except the sides, im gonna have to do that when i get the box mocked up and whatnot. Getting all the cutting done wasnt as bad as i thought though :)


The design i went with. Ended up being around 5-6 cubes net after sub displacement and stuff i think. Around 1.75 per sub is about perfect i guess. Max recommended sealed is 2 cubes,

02-12-2009, 09:43 PM
You are a ******* retarded :fyi:

wow....if your gonna insult the man...at least spell it right. Its "RETARD"