1. Polygons
Two-dimensional shapes that have three or more sides made from straight lines.
Examples:
triangles
squares
rectangles

2. Sides The lines you can trace and count on the outside of a 2D shape.
Example: A triangle has 3 sides. A square has 4.

3. Parallelogram
A quadrilateral with parallel opposite sides of equal length.
Opposite angles are equal.

4. Quadrilaterals
Any two-dimensional shapes (polygon) with 4 straight sides and 4 angles
The interior angles of a Quadrilateral add up to 360 degrees.
Ex.
rhombus kite
rectangle trapezoid
square

5. Rectangle
A 2D shape with 4 corners and 2 pairs of opposite, equal, parallel sides.
The sides meet at right angles.

6. Rhombus A 2D, four-sided shape with opposite sides that are parallel.
All the sides are the same length.

7. Rhombus A 2D, four-sided shape with opposite sides that are parallel.
All the sides are the same length.
Diagonals of a Rhombus bisect each other at right angles.

8. Trapezoid A 2D shape (polygon) with four sides.
One pair of sides is parallel.

9. Trapezoid A 2D shape (polygon) with four sides.
One pair of sides is parallel.

10. Square 2D shape (polygon) with 4 equal sides and 4 right (90°) angles.
Opposite sides are parallel.

11. Triangle
Two-dimensional shape (polygon) with three straight sides and three angles.
The interior angles of a triangle add up to 180 degrees.
There are
isosceles triangles,
right triangles
equilateral triangles
scalene triangles

12. Isosceles Triangle
A triangle with equal sides and 2 equal angles

13. Equilateral Triangle
A triangle with equal sides and 3 equal angles.

14. Right Triangle
A triangle with one right angle (90 degrees).

15. Scalene Triangles
A triangle with 3 different side lengths and 3 different angle measures.

16. Congruent
Two figures are congruent if they have the same shape and size.
Two angles are congruent if they have the same measure.

17. Rectangular Prism A 3D shape that has: 6 rectangular faces
2 of those faces are equal
12 edges
8 vertices
Some faces are parallel
Some edges are parallel
Some faces are perpendicular
Some edges are perpendicular

18. Pyramid
A three-dimensional shape which has a polygon for its base and triangular faces which meet at one point (vertex).

19. Cube
A three-dimensional shape which has 6 square faces all the same size, 12 edges and 8 vertices.
Some faces parallel
Some edges parallel
Some faces perpendicular
Some edges perpendicular

20. Line An infinitely long, thin, two-dimensional mark
It has no endpoints.

21. Line Segment A section of line bounded by two endpoints.
A line segment is not continuous.

22. Intersecting
Crossing over one another.
These lines are intersecting.

23. Parallel Lines that are the same distance apart from each other.
These type of lines stay the same distance apart for their whole length. They do not need to be straight or the same length.
They never intersect.

24. Perpendicular
Lines that intersect at a perfect right angle (90º) to one another.
In solid shapes, edges could be at a right angle to one another.
Faces could also be at right angles to one another.

25. Angles
A shape formed by two lines or rays that extend from a common point (vertex).
The amount of turning between two lines that meet at a common point (vertex).

26. Vertex (angles)
The common point between two or more rays or line segments.

27. Right Angle
An angle whose measure is exactly 90 degrees.

28. Symmetry
An object is symmetrical when you can fold it in half and the two halves are congruent.
One half is a mirror image of the other.

29. Symmetrical Not Symmetrical