Structural Engineer Costs. Homeowners spend an average of $512 on hiring a structural engineer, with most homeowners spending between $319 and $708. The larger and more detailed the project is, the higher the cost of hiring a structural engineer becomes. Some professionals charge by the job, while others may charge by the hour.
The total surface area of Earth is about 197 million square miles (509 million square km). About 71 percent is covered by water and 29 percent by land.
The Earth's Diameter is 7926.41 miles. The surface area of Earth is (pi x Diameter) = 197.38 million square miles (where pi = 3.14159265358979). However, the Earth only has 57 million square miles of land (that's 36.48 billion acres; there are 640 acres per square mile). However, there are only 12 million square miles (7.68 billion acres) of arable land.