The lower arm vector is .

The middle arm vector is .

The upper arm vector is .

(a)

Find a vector that represents the position of the hand.

From the diagram:

The position of the hand .

.

The position of the hand vector is .

(b)

Determine the distance of the hand from the origin.

The position of the hand vector is .

The points are  and .

If  and  are two points in space, the distance from  is

.

Here and .

.

The distance of the hand from the origin is .

(a) The position of the hand vector is .

(b) The distance of the hand from the origin is .