Oral route. Many drugs can be administered orally as liquids, capsules, tablets, or chewable tablets. Because the oral route is the most convenient and usually the safest and least expensive, it is the one most often used. However, it has limitations because of the way a drug typically moves through the digestive tract.
Measuring Distances to Stars. Astronomers use several techniques for discovering how far away an object is. The first is called trigonometric parallax and is based on geometry, but it is only good for up to about 500 light-years.
As a curiosity, there's even a unit in Astronomy, the parsec (I bet you have heard of it in science fiction) which is exactly the distance of a star for which the angle A would be 1/360 degreees (1 arc-second). However, again, this technique is only good for relatively short distances,at most about 500 light years.