Question 346000
Treat the Earth as a sphere.
The perimeter would be the circumference of a circle with radius 6400 km.
{{{C=2*pi*6400}}}
{{{C[1]=40212}}}km
Now if we add 20 km,
{{{C[2]=40212+20}}}
{{{C[2]=40232}}}km
Find the radius of the circle with that perimeter,
{{{2*pi*R=40232}}}
{{{R=6403}}} km
The difference in radii is
{{{dR=6403-6400}}}
{{{dR=3}}}km
You could easily fit yourself under that, in fact, on a cloudy day you wouldn't even see the wire.