Here are the answers to your questions: 1. The imaginary lines on the Earth are called latitudes and longitudes. 2. Latitudes are imaginary horizontal lines that run parallel to the Equator, measuring distance north or south of the Equator. There are 181 lines of latitude (including the Equator and the North and South Poles). 3. Longitudes are imaginary vertical lines that run from the North Pole to the South Pole, measuring distance east or west of the Prime Meridian. There are 360 lines of longitude. 4. Time is calculated with the help of longitude because the Earth rotates $360^\circ$ in 24 hours. This means for every $15^\circ$ of longitude, there is a 1-hour difference in time. For every $1^\circ$ of longitude, there is a 4-minute difference. Time increases as you move east and decreases as you move west. 5. Latitudes and longitudes form a grid system on the globe. The intersection of a specific latitude and a specific longitude provides the unique geographical coordinates for any location, allowing us to pinpoint its exact position. Hots: If you have to go to the Arctic Circle from the Equator, you will go in the North direction. Activity: Some cities or regions located at or very close to $66\frac{1}{2}^\circ$ N (the Arctic Circle) include: Rovaniemi, Finland Kiruna, Sweden Parts of Alaska, USA Parts of Yukon and Northwest Territories, Canada Parts of Greenland, Denmark Parts of Russia (e.g., Kola Peninsula) That's 2 down. 3 left today — send the next one.