A. when three or more lines, rays, or segments intersect in the same point. b. a relationship between two quantities, written a to b, a: b, or a/b c. polygons that have the same shape (same angles) and proportional sides. d. the perpendicular segment from a vertex to the opposite side or to a line that contains the opposite side. e. when something is the same distance from two or more places. f. the point of concurrency of the three angle bisectors of a triangle. g. finding measurements using techniques of similar and congruent triangles, instead of directly measuring the distance. h. a segment, ray, line, or plane that is perpendicular to a segment at its midpoint i. if a point is on the bisector of an angle, then it is equidistant from the two sides of the angle. j. two equivalent ratios