Fig. 54.
SYMMETRY.—Design. A proper adjustment or adaptation of parts to one another and to the whole.
TRISECT.—To divide into three equal parts.
TRIANGLE.—A triangle is a polygon having three sides and three angles. Tri is a Latin prefix signifying three; hence a Triangle is literally a figure containing three angles.
A Scalene Triangle is one in which no two sides are equal. See [fig. 50].
An Isosceles Triangle is one in which two of the sides are equal. See [fig. 51].
An Equilateral Triangle is one in which the three sides are equal. An Equiangular Triangle is one having its three angles equal. An Acute-Angled Triangle is one in which each angle is acute.
A Right-Angled Triangle is one which has one of the angles a right angle. See [fig. 53].
An Obtuse-Angled Triangle is one having an obtuse angle. [Fig. 54].
Equiangular triangles are also equal sided, and vice versa.