text: Lisbon, Portugal's latitude is approxiametley 38.42N. Equator is 0. If you divide the circumference of the earth (approximately 25,000 miles) by 360 degrees, the distance on the earth's surface for each one degree of latitude or longitude is just over 69 miles, or 111 km. Note: As you move north or south of the equator, the distance between the lines of longitude gets shorter until they actually meet at the poles. At 45 degrees N or S of the equator, one degree of longitude is about 49 miles. \n I don't know how exact your answer has to be but roughly its the degree(38.42) x 69 = 2650.98 That does not take into account the fact that every latitude number is actually smaller than the previous as noted.