The rule we will use is
[tex]\parallel AB\parallel=\sqrt[]{(x2-x1)^2+(y2-y1)^2+(z2-z1)^2}[/tex]x1 = 2 and x2 = 6
y1 = -3 and y2 = 7
z1 = -4 and z2 = -4
[tex]\parallel AB\parallel=\sqrt[]{(6-2)^2+(7--3)^2+(-4--4)^2}[/tex]Now we will find the answer in decimal using the calculator
The answer is 10.77032961
Round it to 3 decimal places, then
[tex]\parallel AB\parallel=10.770[/tex]