Find the distance in 3-space?

Question

Find the distance from (2, 3, -1) to the:

a) xy-plane

b) y-axis

c) the origin

Answer 1

its c

Answer 2

c) origin = (0,0,0)

d^2=(2-0)^2+(3-0)^2+(-1-0)^2

d^2 = 4+9 +1 =14

distance = sqrt(14)