1. Vertex the point where two lines, line segments, or rays meet to form an angle Point A is a vertex for the angles formed. A

2. sequence A set of numbers arranged in a certain order or pattern 2, 4, 6, 8, 10 3, 6, 3, 9, 3, 12

3. measure of an arc The degree measure of an arc is equal to the measure of its central angle.

4. Rhombus Quadrilateral with four equal sides

5. Diagonal Line segment that joins two vertices of a polygon, but is not a side of the polygon Diagonals

6. bisect To divide into two equal parts, cut in half

7. apothem Segment from the center of a polygon perpendicular to the side of the polygon apothem

8. Central angle Angle in a circle with its vertex at the center of the circle

9. Vertical angles  The opposite angles formed when two lines intersect 1 4 3 2

10. reciprocals Two numbers that have a product of 1

11. edge  Line segment where two faces of a solid figure meet edge

12. face  Plane figure that serves as one side of a solid figure face

13. polygon  A closed figure formed from line segments that meet only at their endpoints

14. Perpendicular lines Two lines that intersect and form a right angle

15. Prime notation When figures are transformed, prime notation is often used to name the image. The point P’ (read P prime) is the image of point P Reflect D ABC across the x-axis D ABC  D A’B’C’ x y

16. Tesselation Repeating pattern of figures that fills a plane completely No overlapping of figures, no gap between figures

17. Tangent to a circle Line that intersects the circle in exactly one point Is perpendicular to the radius of the circle at the point of intersection, called point of tangency

18. Quadratic formula Used to find the solution to a quadratic equation in standard form x 2 + bx + c = 0

19. Favorable event or outcome In probability the outcome your are interested in measuring Example: Rolling two dice and getting a one on each die.

20. Perpendicular bisector Line, line segment, or ray that is perpendicular to a line segment at its midpoint Line DE is perpendicular to segment AC at midpoint B. DE is the perpendicular bisector of segment AC.

21. cone Three dimensional figure with one vertex and one circular base Vertex Base

22. Conditional statement Statement in the form of If ___, then ___. If an angle is a right angle, then its measure is 90 o. If a triangle is a right triangle, then it has a right angle.

23. transversal  A line that intersects two or more lines transversal

24. secant of a circle A line that intersects a circle in two points

25. Regular polygon Polygon that is equiangular (all angles are equal) and equilateral (all sides are equal Regular quadrilateral (square) Regular triangle, (equilateral and equiangular) Regular pentagon Regular hexagon