What is the land area of earth in square miles? Round off to two significant digits

Question

There are about 150 million km2 of land on earth and almost 7 billion humans.

2.6 km2 = 1 mi2 = 640 acres = 260 hectares                            1 hectare = 2.5 acres

Answer 1

2.6 square km=1 sq mile so 150 million sq km=150/2.6 million sq mile=57.69 million sq mile approx = 58 million square miles to two significant figures. All other figures are irrelevant to the solution.

Answer 2

1 sq km=0.38610071 sq mile times 150 milyun sq km... 0.38610071*1.5*10e8=0.579151*10^8 sq mile...0.57915e8 round2(0.579151)=0.58

Comments

0.58E8=58E6=58 million sq miles. You were nearly there! But you didn't use the conversion info in the question!