XXVI. Of theſe Trilateral figures, a right-angled Triangle is that which has one right angle; as the Triangle A.
XXVII. An Amblygonium, or obtuſe-angled Triangle, is that which has one angle obtuſe; as B.
XXVIII. An Oxygonium, or acute-angled Triangle, is that which has three acute angles; as C.
An Equiangular, or equal-angled figure is that whereof all the angles are equal. Two figures are equiangular, if the ſeveral angles of the one figure be equal to the ſeveral angles of the other. The ſame is to be underſtood of Equilateral figures.
XXIX. Of Quadrilateral, or four-ſided figures, a Square is that whoſe ſides are equal, and angles right; as ABCD.
XXX. A figure on the one part longer, or a long ſquare, is that which hath right angles, but not equal ſides; as ABCD.
