+194 Assume that the length of Earth's equator is exactly 25,100 miles and that the Earth 45˚ North Latitude, exactly halfway between the equator and the North Pole. What is the number of miles in the circumference of the circle on Earth parallel to the equator and through Lena, Wisconsin? Express your answer to the nearest hundred miles. (You may use a calculator for this problem.)
+128475 We need to find the radius of the Earth as follows :
25100 = 2 pi * radius
25100 / [ 2 pi] = radius
12550 / pi = radius [in miles]
At 45°, the radius of the smaller circle parallel to the equator running through Lena will be =
12550 / [ √2 pi] miles
So....the circumference of this smaller circle will be =
2 pi [ 12550 / (√2 pi ) ] =
√2 * 12550 ≈ 17,748 miles = 17,700 miles
