triander

[TRI AND RIA.] 4176 opposite angle is called the vertex of the triangle; the distance from the vertex to the base is the altitude. Any side of a triangle may be regarded as a base, though in the right-angled triangle one of the sides about the right angle is usually taken. The three angles of a plane-triangle are together equal to two right angles, or 180°; its area is equal to half that of a rectangle or parallelogram having the same base and altitude; in a right-angled plane triangle the square of the side opposite the right angle is equal to the sum of the squares of the other two sides. 6. Mil .: A sort of frame formed of three halberds to which a person was lashed to undergo military punishment. (Not used now.) [HALBERD, 1.] 7. Music : A bar of steel bent into the form of a triangle, having an opening at one of the lower angles, so that the sides are of unequal length. It is suspended by one angle and struck with a small rod, and is sometimes introduced in brilliant musical pa ages. 8. Pottery : A small piece of pottery, placed bevent the adherence of the pieces when fired. tween pieces of biscuit ware in the seggar, to pre 9. Surveying : Since every plane figure may be regarded as composed of a certain number of tri. angles, and as the area of a triangle is easily computed, the whole practice of land-surveying is nothing more than the measurement of a series of plane triangles. 2. Botany : tri a no sperm a (1) ( Of a leaf ): Having the figure of a triangle of any kind; as the leaf of Betula alba . (2) ( Of a stem, .): Three-edged, having three acute angles with concave faces, trigonal.