How much of the Earth's land is tillable?
494215
If by "tillable" you mean "arable": i.e., land that can be used for growing crops, then about 12 million square miles (31,000,000 km²). That's about 21% of the planet's land area.
100786
Surface Area: Land area, about 148,300,000 sq km, or about 30% of total surface area; water area, about 361,800,000 sq km, or about 70% of total surface area.
815939
Not sure I understand your question....\nThe total mass of the earth is 6x10^24 kg.\nThe total human world population is about 6.6 x 10^9. Assuming an average weight of 50 kg, this give a total human mass of 3.3 x 10^11 kg, far smaller than the earth.  \nThe total biomass (all plants and animals together) is estimated here\nhttp://en.wikipedia.org/wiki/Biomass\nat about 2x10^15 kg, still 9 orders of magnitude smaller than the mass of the earth.
171299
Africa is the world's second-largest and second most populous continent, after Asia. At about 30,370,000 km² (11,730,000 sq mi) including its adjacent islands, it covers 5.9% of the Earth's total surface area, and 20.3% of the total land area. With over 840,000,000 people (as of 2005) in 61 territories, it accounts for more than 12% of the world's human population.
498611
Land is rocks, minerals, and soil all in one to form the planet's surface. (excluding the surface covered by water.) The factors of land are: It can be moved and reshaped (in its mud form), It absorbs water and it holds vegatation down. Land can be increased by spreading out the hills to cover more surface, which would require covering up water.
389747
http://hypertextbook.com/facts/2001/DanielChen.shtml\n\nEarth has a surface area of 196,940,400 square miles, slightly less than a perfect ball with a diameter of 7913.5 miles (which is the mean diameter of the Earth - see "Prove it" under 103).\n\nhttp://pages.prodigy.net/jhonig/bignum/qland2.html
372831
irrigate - 1.8 million hectares\n\nsorry that's all
297260
Earth is 12,742 kilometers (7,900 miles) in diameter.
664993
75% of the earth...u do the rest of the calculation.
199932
The earth's rotation.
66810
Earth ranges from 7,926 miles to 7900 miles, depending on your location.\n\nThis is approximately 12,756km
555817
Approximately 600 kilometers (372 miles)above the surface of the Earth
984374
Well, that depends.  There is evidence of algae at 3.5 billion, probably photosythetic cells by 2.0, and clear plants by 400 million.  With a 4.6 billion year old earth, that's 76%, 43%, or 8.7% of the time.
680258
Water! Most of the earth is covered with water.
464580
About 8000 miles.\n\nThe radius of the earth is approx 3959 miles - you would have to dig twice that distance, or 7918 miles.
383964
You can cram in over six billion\nhttp://www.solarviews.com/raw/earth/earthafr.jpg\n\nI second the motion for Mosaic\nhttp://chrisboy.com/oly/ol_face_4_mosaic.jpg
438648
The Moon has a surface area of 152 million square kilometers.\nThe Earth is 13.5 times larger.