Hi all,(adsbygoogle = window.adsbygoogle || []).push({});

Ifa,b,c,dare position vectors of four points A,B,C,D.The points will be coplanar if xa+yb+zc+td=0,x+y+z+t=0,provided x,y,z,t are not all 0,and they are scalars.Is this test needed to show 4 points are coplanar?

If we consider two lines joining A,B and C,D then this will give us two vectors which are always coplanar.So points A,B,C,D are also coplanar.So I assumed that any 4 points are coplanar and no test is needed for it.

Or is this the test to verify coplanarity of D with the plane containing A,B,C ?

I'm wondering if my assumption is true?Please help me clarifying it.

I'm new here ,Please treat my mistakes with forgiveness.

Thanks.

1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Test for coplanarity of four points

**Physics Forums | Science Articles, Homework Help, Discussion**