Determining Coplanarity of four points

  • Thread starter Thread starter jrotmensen
  • Start date Start date
  • Tags Tags
    four points Points
Click For Summary
SUMMARY

To determine the coplanarity of four points A(3,1,0), B(2,-3,1), C(-1,0,4), and D(5,-6,-2), one can use the equation of a plane derived from three points. The equation can be expressed as Ax + By + Cz = 1 or Ax + By + Cz = 0, depending on whether the plane includes the origin. By substituting the coordinates of the fourth point into the plane equation, one can verify if it lies on the same plane as the other three points. This method does not require vector multiplication, making it accessible for those unfamiliar with that concept.

PREREQUISITES
  • Understanding of 3D coordinate geometry
  • Familiarity with the equation of a plane
  • Basic algebra for solving equations
  • Knowledge of vectors and their properties
NEXT STEPS
  • Study the derivation of the equation of a plane from three points in 3D space
  • Learn about vector operations, specifically cross product and dot product
  • Explore the concept of coplanarity in higher dimensions
  • Practice solving problems involving the coplanarity of points in 3D
USEFUL FOR

Students and educators in mathematics, particularly those focusing on geometry and vector analysis, as well as anyone involved in computer graphics or spatial analysis requiring an understanding of point relationships in three-dimensional space.

jrotmensen
Messages
3
Reaction score
0
How do you determine Coplanarity of four points?
I am given A(3,1,0), B(2,-3,1), C(-1,0,4), D(5,-6,-2).

Do i make vectors for each point from the origin? (But that wouldn't work would it? :()
Can anybody point me in the right direction?

Thanks!
 
Physics news on Phys.org
if a,b,c are coplanar vectors then
a.(bxc)=0
 
rock.freak667 said:
if a,b,c are coplanar vectors then
a.(bxc)=0

at this point, we haven't learned vector*vector multiplication.
is there any other way?

also, how should i get the vectors? displacement of the point from the origin? or displacement from one point to another??
 
Last edited:
The equation of any plane (that does not include the origin) can be written in the form Ax+ By+ Cz= 1. Replace x, y, and z by the coordinates of three of your points to get three equations to solve for A, B, and C. (If you can't, it is because the plane includes the origin- so try again with Ax+ By+ Cz= 0.)

Once you have the equation of the plane that contains three of the points, put the coordinates of the fourth point into that equation and see if they also satify the equation.
 

Similar threads

  • · Replies 2 ·
Replies
2
Views
1K
Replies
2
Views
2K
Replies
6
Views
3K
Replies
3
Views
1K
  • · Replies 4 ·
Replies
4
Views
7K
  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 7 ·
Replies
7
Views
3K