The map shows a top view of the Mississippi River. The gap between lines 1 and 2 shows how much Saint Anthony Falls receded betw
een 1680 and 1766. The gap between lines 3 and 4 shows how much the falls receded between 1856 and 1876. At what rate (on average) did the falls recede during each of these time spans? Express your answer in units of feet per year. Did the rate increase or decrease from one time span to the next? Hint: Determine how many years passed between lines 1 and 2 and between lines 3 and 4 to help you find your answers.
The time span between 1680 and 1766 (lines 1 and 2) is 86 years: 1766 − 1680 = 86 years. During this time, the falls receded an average of 5.8 feet per year: 500 feet ÷ 86 years ≈ 5.8 feet per year.
The time span between 1856 and 1876 (lines 3 and 4) is 20 years: 1876 − 1856 = 20 years. During this time, the falls receded an average of 25 feet per year: 500 feet ÷ 20 years = 25 feet per year.
The time span between 1680 and 1766 (lines 1 and 2) is 86 years: 1766 − 1680 = 86 years. During this time, the falls receded an average of 5.8 feet per year: 500 feet ÷ 86 years ≈ 5.8 feet per year.
The time span between 1856 and 1876 (lines 3 and 4) is 20 years: 1876 − 1856 = 20 years. During this time, the falls receded an average of 25 feet per year: 500 feet ÷ 20 years = 25 feet per year.
Sunna
in Yemen . Overall in the Arabian Peninsula most rain falls in the
South West, and up along the Red Sea coast in the southern half of the
Peninsula. and along the western half of the south coast/ There is also
some rain in the north east. However there are some parts, particularly
the central and south east that hardly ever see rain. Less than 3 cm per
year.
