Is the Center of Mass Also the Midpoint of a Triangle?

In summary, the midpoint of an arbitrary triangle formed by points A, B, and C is the point at which the lines A->midpoint(B,C) and B->midpoint(A,C) intersect. This point can also be considered the centroid or center of mass of the triangle. However, there are other concepts that could also be called the "midpoint" of a triangle. Only two of the three lines are necessary to define the midpoint, and it can be found by suspending the triangle from a vertex and finding where the three plumb lines intersect.
  • #1
sparkzbarca
7
0
I blieve the mid point in space of arbitrary triangle formed by points A,B,C

is the point at which the line

A -> midpoint(B,C)
B -> midpoint (A,C)
C ->midpoint (A,B)

meet
(i also think C is redundant, that where A to mid and B to mid cross is basically the mid point of
the whole triangle)

Is my math right?

I can't seem to get a clear answer on google

this is for taking a computer model of a shape and finding the midpoint of one face of the model.
(the faces of course are made by connecting points into triangles)
As such it needs to be for an arbitrary triangle (not right angle only for example)
 
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  • #2
What's your definition of the "midpoint" of a triangle? You seem to mean the centroid, but did you know there are three other concepts that could equally validly be called the "midpoint" of a triangle?

See: http://www.mathopenref.com/triangleincenter.html (read that bit about "summary of triangle centres")

If you meant the centroid, yes, that's the way of constructing it, and only 2 of those lines are necessary to define it (the third line will intersect at the same point). The centroid is the most relevant to physical problems like finding the centre of mass of a triangular lamina, so if this is what you're doing, then you're on the right track.
 
  • #3
Curious3141 said:
What's your definition of the "midpoint" of a triangle? You seem to mean the centroid, but did you know there are three other concepts that could equally validly be called the "midpoint" of a triangle?

I don't really want to hijack this thread, but there are 5427 possible notions of the center of a triangle :biggrin:
See http://faculty.evansville.edu/ck6/encyclopedia/ETC.html
 
  • #4
micromass said:
I don't really want to hijack this thread, but there are 5427 possible notions of the center of a triangle :biggrin:
See http://faculty.evansville.edu/ck6/encyclopedia/ETC.html

Whoa. You mathematician types obviously have nothing but time on your hands...or in your case, flippers, since you're a walrus. :smile:
 
  • #5
Oops

"I can't seem to get a clear answer on google".

Well, I tried for myself, using "midpoint of triangle" for searching.

Lots of results.
 
  • #6
If you imagine the triangle as a piece of perfectly uniform cardboard, then the mid point you are speaking of is the center of mass of the triangle.

Suspend the triangle by a vertex in a gravitational field and let it hang freely . A plumb line dropped from the vertex will pass through the center of mass (center of gravity) for other wise the center of mass would exert a torque on the vertex. Since this is true starting from any vertex, the three plumb lines must intersect at the center of mass.

You are right that you only need two of these lines to find this point.

Can you show that this three sides are intersected at their midpoints?
 
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FAQ: Is the Center of Mass Also the Midpoint of a Triangle?

What is the definition of the mid point of a triangle?

The mid point of a triangle is the point that is equidistant from all three vertices of the triangle. In other words, it is the point that divides each side of the triangle into two equal segments.

How do you find the mid point of a triangle?

To find the mid point of a triangle, you can use the midpoint formula (x1 + x2)/2, (y1 + y2)/2 where (x1,y1) and (x2,y2) are the coordinates of any two vertices of the triangle.

Can the mid point of a triangle be located outside of the triangle?

No, the mid point of a triangle will always lie within the triangle itself. This is because it is equidistant from all three vertices, so it must be contained within the triangle's boundaries.

What is the significance of the mid point of a triangle in geometry?

The mid point of a triangle is important in geometry because it can be used to find the center of mass of the triangle, as well as to calculate the distance between the mid points of different sides. It can also be used to bisect angles and sides of a triangle.

Does every triangle have a unique mid point?

Yes, every triangle has a unique mid point. This is because the mid point is determined by the coordinates of the triangle's vertices, and each triangle has a unique set of vertices. So even if two triangles have the same shape and size, they will have different mid points.

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