Angle An angle is formed when two rays share a common vertex. Area The surface area of two-dimensional figure. Model A mathematical model based on the rectangle used to represent multiplication or fractional parts whole. Arithmetic Sequence sequence a1 a2 a3 a4... an arithmetic if there number c such that for each n + 1= c 1 – = c. Associative Property Addition For any numbers x y and z: (x y) z= x (y z). Attribute distinguishing characteristic object as angles sides triangle. Average See: Mean. Axis line in plane. Plural form axes. Also see: Coordinate Plane. Bar Graph graph which rectangular bars either vertical horizontal are display data. Circle set points plane equidistant from point Pie graph. Circumference distance around circle. Its length product diameter circle pi. Coefficient In constant variable numerical coefficient frequently referred simply coefficient. Combining Like Terms nk nm= n(k m). commonly called factoring. Common Denominator multiple denominators more fractions. Least Factor factor integers have common. Greatest Factor. Multiple Multiple. Commutative y: x. Multiplication b: ab= ba. Complement complement all elements universal not given set. Complementary Angles Two complementary sum their measures totals 90º. Congruent Used refer having same measure polygons shape size. Conjecture assumption thought be true observations. Constant fixed value. Proportionality If function has rule y= Kx then input x?0 quotient y/x will always value K. K proportionality. Rate Of Change mx b here m rate change. Another term scale factor. Coordinate(s) assigned shows its position location line. coordinate ordered pair (xy) showing relation x-axis y-axis. Plane consists horizontal line intersecting at right origins. lines axes divide into four quadrants. quadrants numbered I II III IV beginning upper quadrant moving counterclockwise.