How many miles of paved roads are there in the U. S.? How would you attempt to find the answer?

(The solution number isn't exactly important here, more like the critical thinking of how you got that with the process)
ie. Factoring density, grouping of more dense states, less dense states, or the ratio between paved roads and people. Any ideas? Thanks!

What is the general rule about surface currents? cold water flows along the ocean floor towards the equator. the east coasts of continents have cold surface currents, and the west coasts of continents have warm surface currents. seasonal and constant offshore winds create significant upwelling along the west coasts of south and north america and africa. the west coasts of continents have cold surface currents, and the east coasts of continents have warm surface currents.

Which outcome is not caused by gravitational forcea. gas and dust come together to form a planet b. planets orbit a star c. two atoms come together to form a molecule d. stars cluster to form a galaxy

Which barrier to economic development is shown in the following examples?