7 981 943 000 Millimeters
There is no limit to the area that the dog can access and explore. It can go anywhere it wants to, and simply drag the leash behind. My dogs do it all the time. Now if you were to fasten the free end if the leash to a stake in the ground, then the situation would be a completely different one. Then the dog would be restricted to the circle centered at the stake with radius=4 meters. The area of such a circle is 16 pi square meters.
Just subtract a number below 10 and get a answer
Whatb is the measure of what ? please complete this your question
