# 3-D Vectors

1. Sep 21, 2007

### chemguy990

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

I am having a tough time finding the resultant vector of the the following three dimensional vector:

d1x=2.33 cm, d1y= 3.84 cm, d1z= -1.2cm
d2x=3.41 cm, d2y= -1.01 cm, d2z = -3.29 cm
d3x= -1.04 cm, d3y= 1.93 cm, d3z = 0 cm

Find the resultant vector magnitude.
2. Relevant equations

3. The attempt at a solution

I have added the vector components and got the following:
rx= 4.7, ry= 4.76, rz= -4.49

Not sure where to go next.
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

Last edited: Sep 21, 2007
2. Sep 21, 2007

### CompuChip

So you have calculated the sum of the three vectors (the resultant vector). Now how do you get its magnitude?

3. Sep 21, 2007

### chemguy990

I know using the pythagorean theorem will get the resultant for xy plane vectors...not sure how to get the third plane calculations.

4. Sep 21, 2007

### learningphysics

You'd apply pythagorean a second time, using the z-vector and the xy plane vector... draw a picture if you are unsure...

so the magnitude of the resultant is just $$\sqrt{r_x^2 +r_y^2 + r_z^2}$$