Question

What is the distance from the point (4,4,10) to the z axis?

Answer 1

Can you guess which point on the z-axis is closest to (4,4,10) ?

Answer 2

0,0,10

Answer 3

Right. Do you remember the distance formula between two points given by their coordinates?

Answer 4

(x2-x1)^2 + (y2-y1)^2 + (z2-z1)^2 all under a square root?

Answer 5

Yes, from the Pythagorean theorem in 3 dimensions.

Answer 6

Okay so I do 4,4,10 and 0,0,10 in distance formula?

Answer 7

Yes. That's how you define the distance between a point and a line. Find the point on the line that's closest to the point and then find their distance.