Mrs. Daniel s Geometry Vocab List

Transcription

1 Mrs. Daniel s Geometry Vocab List

2 Geometry Definition: a branch of mathematics concerned with questions of shape, size, relative position of figures, and the properties of space.

3 Reflectional Symmetry Definition: All of the points on one side of the line exactly match with all of the points on the other side of the line.

4 Definition: looks that same after you turn the image around a point by less than 180 degrees. The number of times you can turn the image determines the type of rotational symmetry. Rotational Symmetry

5 Point Definition: Location only; it has no size. How to Name: One capital letter. Example: P

6 Line Definition: Straight continuous arrangement of infinitely many points. How to Name: Two capital letters with a line with 2 arrows above it. Example: CD

7 Plane Definition: Flat surface that extends infinitely along its length and width. How to Name: One capital script (cursive) letter. Example: M

8 Collinear Definition: On the same line

9 Coplanar Definition: On the same plane

10 Ray Definition: A point on a line, and all the points that lie on one side of this point. How to Name: Two capital letters and a line with one arrow above. The endpoint must be the first letter. Example: FR

11 Line Segment Definition: Part of line. Does not extend indefinitely. How to Name: Two capital letters and a line on top. Example: AB

12 Midpoint Definition: Point on a line segment that is the same distance from both end points. (must be drawn with tic marks)

13 Congruent Definition: Equal. The same length. The same size. The same measure. Drawn with tic marks.

14 Bisects/Bisector Definition- Divides into two equal, congruent parts. Line: divides into two congruent segments Angle: divides into two congruent angles (must be drawn with tic marks)

15 Angle Definition: Formed by two rays that share a common endpoint. How to Name: One or three letters. Angle symbol ( ) in front. Example: B or ABC

16 Vertex Definition: Common endpoint of the two rays in an angle

17 Perpendicular/Perpendicular Bisector Definition: Lines that meet at a 90 degree angle. Symbol: For example: AB CD (must be drawn with right angle mark)

18 Parallel Definition: Lines that never intersect (cross/touch). Symbol: Example: ST CG

19 Complementary Angles Definition: 2 angles that add up to 90 degrees.

20 Supplementary Angles Definition: 2 angles that add up to 180 degrees.

21 Linear Pair of Angles Definition: Two angles on one line. Sum to 180 degrees.

22 Right Angle Definition: Angle measure of exactly 90 degrees. Symbol: Drawn with a box

23 Acute Angle Definition: Angle measure of less than 90 degrees.

24 Obtuse Angle Definition: Angle measure of more than 90 degrees, but less than 180.

25 Polygon Definition: A closed figure. How to Name: All capital letters. Use as many letter as sides to the polygon. Some Examples:

26 Concave Definition: Polygon dips inward (Some diagonals can be drawn outside the shape).

27 Convex Definition: Polygon only points outward. (No diagonals can be drawn outside the shape).

28 Regular Polygon Definition: A closed figure, with congruent sides and congruent angles. All sides and angles marked congruent.

29 Perimeter Definition: Sum of the lengths of the sides. Perimeter = 26cm

30 Area Definition: The amount of space inside the boundary of a flat (2-dimensional) object such as a triangle or circle.

31 Right Triangle Definition: A triangle with one 90 degree angle. Marked with box

32 Acute Triangle Definition: A triangle with three acute angles.

33 Obtuse Triangle Definition: A triangle with one obtuse angle.

34 Scalene Triangle Definition: Triangle with no congruent sides. Each side is marked with a different number of hash marks.

35 Isosceles Triangle Definition: Triangle with at least two congruent sides and two congruent angles. Picture: Marked with two congruent sides and two congruent angles.

36 Equilateral Triangle Definition: Triangle with three congruent sides and angles. Marked with three congruent sides and three congruent angles.

37 Quadrilateral Definition: Any closed four-sided figure. Some Examples:

38 Parallelogram Definition: A quadrilateral with two pairs of parallel sides. Marked parallel and congruent.

39 Rhombus Definition: Two pairs of parallel sides and 4 congruent sides. Marked parallel and congruent.

40 Rectangle Definition: Two pairs of parallel sides and 4 congruent angles Marked parallel, congruent and 4 right angles.

41 Square Definition: 4 congruent sides and 4 congruent angles Marked parallel, congruent and four right angles.

42 Circle Definition: a set of all points in a plane at a given distance from a given point (center/origin).

43 Radius/Diameter Definition: The given distance from center/origin of the circle to the edge. Diameter is a chord that passes through the origin/center.

44 Chord Definition: A line segment whose endpoints lie on the circle. The diameter is the longest chord.

45 Tangent Definition: A line that touches (intersects) the circle only once. The point the circle touches the circle is named the point of tangency.

46 Semicircle Definition: Half of a circle.

47 Cylinder Definition: a solid geometric figure that is composed of two parallel congruent circles (bases) and a rectangle as a lateral face.

48 Prism Definition: solid geometric figure that has two parallel congruent bases that are connected by lateral faces that are parallelograms

49 Sphere Definition: a round solid figure, or its surface, with every point on its surface equidistant from its center.

50 Cone Definition: solid geometric figure that has a flat base (frequently, though not necessarily, a circle) and tapers to a point called the apex or vertex.

51 Pyramid Definition: solid geometric figure formed by connecting a polygonal base with a point forming triangular lateral faces.