Density of an object is defined as (mass)/(volume).
Well, a 2D object has only length and width, but a 3D object has length, width, and depth.
Paper is a 3D object.
A sphere.
A Heptagon is a 3d object with 7 faces. An example of a heptagon is a hexagonal pyramid (that is a pyramid with a hexagon for the base).
3D
what is the formula for finding a 3 dimensional square
Well, a 2D object has only length and width, but a 3D object has length, width, and depth.
a 3d object is a object that isn't flat. for instance, a square in 3d form would be a cube
a 2D object is is flat and on the other hand a 3D object is bulgy
Paper is a 3D object.
on a 3D object to find the surface is to look on all flat surfaces. yourwelcome
Um... What?
A sphere.
Maybe a circle and a triangle, and indeed a straight line are not 3D.
You can't find the perimeter of a cone because it's a 3D shape, but you can find the volume; the formula is 1/3x3.14xr2xh (r= radius of the base/ h= height).
length x breadth x height=3d
It is the volume of the object.