1. Geometry Vocabulary Chapter 8

2. POINT A POINT is an exact location on a graph, shape or in “space”. The Hershey Kiss is a POINT on the line ●

3. LINE A LINE goes in opposite directions and never, never, never ends. Imagine if this Twizzler went on forever and ever and ever and ever and ever and ever

4. RAY A RAY is part of a line, but it has one endpoint and the other end keeps going. ● Endpoint Raaaaaaaaaaaaaaaaaaaaaaaayyyyyyyyyyyyyyyyyyyyyyyyyyy

5. LINE SEGMENT A LINE SEGMENT is part of a ray or line. It has two endpoints ●● Line Segment Line Ray ● Endpoints

6. VERTEX A VERTEX is a fancy name for angle Two rays or lines that have the same endpoint make a VERTEX/angle VERTEX/angles are measured in “degrees” The Corners of a square are its vertex/angles When two lines cross, they make vertex/angles

7. CONGRUENT CONGRUENT means the “same” CONGRUENT LINE SEGMENTS means two line segments are the same CONGRUENT Vertex/Angles means two angles are the same ●● ● ● The Hershey & Crunch Bar are a Congruent size

8. Lines A vertical line goes up & down A horizontal line goes “across” (left and right) The candy bars are vertical The candy bars are Horizontal

9. Lines Parallel lines l || m Perpendicular lines l ┴ m Intersecting lines

10. PLANE A PLANE is a flat surface that goes on forever in all directions. Imagine sitting on a row boat in the middle of the ocean. No matter which way you look…all you see is water…forever.

11. OPEN & CLOSED FIGURES A CLOSED FIGURE/SHAPE starts and ends at the same point. An OPEN FIGURE/SHAPE does NOT start and end at the same point. CLOSEDOPEN ● ● ● Start End Start End

12. POLYGON A POLYGON is a “closed” shape A POLYGON is made up of line segments that do not cross. The number of sides gives a POLYGON its name POLYGON NOT POLYGON

13. Angles Adjacent angles Interior angles (108° angles) Exterior angles (72° angles)

14. Angles ACUTE ANGLES are less than 90° Complementary angles add up to 90° (b + a = 90°) Obtuse Angles are greater than 90 ° but less than 180 ° Supplementary Angles add up to 180° (b + a = 180°)

15. Angles Right angles measure exactly 90 ° Straight angles measure 180 ° The “square” symbol means 90’

16. Angles When you name an angle. The vertex/angle’s letter goes in the center of the label A B C If I wanted to know the measurement of Angle A…I would ask:” What is the measurement for BAC?” (Notice A is in the center)

17. Transversals (line t) Vertical angles = 1 and 3, 2 and 4, 5 and 7, 6 and 8 Alternate interior angles = 3 and 5, 4 and 6 Alternate exterior angles = 1 and 7, 2 and 8

18. Triangles Triangle – a polygon with three sides whose angle sum is 180° Two ways to classify triangles: 1) By side measures 2) By angles measures

19. By side measure Equilateral – all sides congruent (ΔABC) Isosceles – at least two sides congruent (ΔXYZ) Scalene – no sides congruent (ΔRST)

20. By Angle Measures Right – one 90° angle Acute – three acute angles Obtuse – one obtuse angle

21. Quadrilaterals Quadrilaterals have 4 sides and 4 angles Diagonal – a line segment that connects opposite vertices of a closed figure

22. Quadrilaterals Parallelogram Rectangle Square Rhombus Trapezoid

23. Circles Circle – Center – Radius – Chord – Diameter – Central angle –

24. The End Once you study all the “fancy words”, Geometry is very easy to understand…so STUDY!