Which round-the-world trip is shorter. a) along the equator; b) 10 ° N c) 50 ° N d) 70 ° N

To answer this question, let us designate the approximate lengths of each of the four presented parallels.

The length of the equator (zero parallel) is just over 40 thousand kilometers.
The circumference of the Earth is 10 degrees north latitude. is about 36 thousand kilometers.
Length 50 parallel north latitude equal to 17.8 thousand kilometers.
The circular distance along the 70th parallel is only 8.9 thousand kilometers.

The correct answer is option d).