All arcs of circles that are not so great as a semi-circumference are called less arcs. A line that joins the extremities of an arc is called the chord of that arc. When two radii connect together any two points in the circumference of a circle which are on exactly the opposite sides of the centre, they make a chord, which is called the diameter of the circle, and such diameter divides the circle into two equal segments,' which take the name of semicircles. 25. Make a circle, and in it draw two radii in such a position as to divide it into two equal parts, and write on each part its specific name. All segments of a circle which occupy more than a semi-circle are called greater segments. 26. Make a greater segment, and on it write its name. 27. Make a greater segment, and on the outside of each of its boundaries write its name. The word segment means a piece cut off: thus we have segments of a line and segments of a sphere, as well as seg. ments of a circle. All segments of a circle that do not contain so much as a semi-circle are called less segments. 28. Make a less segment, and in it write its name. 29. Make a less segment, and on the outside of each of its boundaries write its name. 30. Can you cut from a circle more than one greater segment? 31. Can you cut from a circle more than one less segment? 32. Place two circles so that the circumference of each may rest upon the centre of the other, and show that the curved figure common to both circles consists of two segments, and may be called a double segment. 33. In how many ways can you divide a double segment into two equal and similar parts? 34. In how many ways can you divide a double segment into four equal and similar parts? 35. Can you make two angles with two lines? |