a small planet and the farthest known planet from the sun; has the most elliptical orbit of all the planets; "Pluto was discovered by Clyde Tombaugh in 1930"
(Greek mythology) the god of the underworld in ancient mythology; brother of Zeus and husband of Persephone
a method of surveying; the area is divided into triangles and the length of one side and its angles with the other two are measured, then the lengths of the other sides can be calculated
a trigonometric method of determining the position of a fixed point from the angles to it from two fixed points a known distance apart; useful in navigation