In astronomy and cosmology, we need to measure times, distances, and angles. Degrees are divided into 60 minutes of arc, and each minute is divided into 60 seconds of arc.
Physicists also use a measure of angle called a radian, defined below.
360 degrees To measure the distance between two objects when the angle between them is known, we use the idea of proportion. The length around the circumference of the circle is proportional to the angle. 2 pi radians. A meter is slightly more than three feet. Because lengths in the universe are so large, we'll want to use some larger units.