9
The four sides are equal as in the square, but the angles are not right angles. To draw this figure, make a right line, cross it with a perpendicular, like the dotted lines in the figure, and then draw the sides.
If the Rhomb or Lozenge have all the angles equal, the figure is merely a square placed obliquely, as in fig. 22.
39.Cut a rectangle into halves.(fig. 23.)
This will make two angles, whose exactness may be tested by an eighth part of a circle of pasteboard, the rectangle being quarter of a circle, as was stated under Prop. 24.
40.Cut an acute angle into two equal parts.(fig.24.)
41.Double an angle.
Make an angle of any size, and then make another of the same size by the side of it. Suppose the lower angle of fig. 24 to be made first, then by making the upper right line, the angle will be doubled.
42.Triple an angle.(fig. 25.)
43.Cut an angle into three equal parts.(fig. 25.)
44.Cut an angle into six equal parts.(fig. 26.)
These three propositions need no explanation.
((gap|3em}}2*
