Suppose that in a country the nautical mile is defined as the length of a minute of arc of the earths radius. Since the earth is flattened at the poles, a nautical mile varies with latitude. In fact, it is given, in feet, by the function N() = 6210 33 cos 2, where is the latitude in degrees. At what latitude north is the length of a nautical mile found to be 6178 ft?

At ______________ N is the length of a nautical mile found to be 6178 ft.

(Simplify your answer. Type an integer or decimal rounded to the nearest tenth as needed.)