1. Basic Geometry
Vocabulary Review

2. Plane and Solid Figures
Plane figure – a plane figure has just 2 dimensions – length and width.
Solid figure – a solid figure has 3 dimensions – length, width, and height.

3. Solid Figures Face – each flat surface of a solid figure
Edge – a line segment where 2 faces meet on a solid figure.
Vertex – “a corner” – where 3 or more edges meet. The plural form of vertex is “vertices.”

4. Solid Figures

5. Polygons
Polygon – a polygon is a closed plane figure made up of line segments. Each line segment is a side.

6. Polygons – Know Your Prefixes!
“Tri” – means 3 – a triangle has 3 sides.
“Quad” – means 4 – a quadrilateral has 4 sides.
“Penta” – means 5 – a pentagon has 5 sides.
“Hexa” – means 6 – a hexagon has 6 sides.
“Hepta” – means 7 – a heptagon has 7 sides.
“Octa” – means 8 – an octagon has 8 sides.
“Nona” – means 9 – a nonagon has 9 sides.
“Deca” – means 10 – a decagon has ten sides.

7. Points, Lines, Line Segments, and Rays
Point – an exact location in space.
Line – a straight path of points that goes on and on in two directions.
Line segment – a part of a line. It has 2 endpoints.
Ray – part of a line. It has one endpoint and continues on and on in only one direction.

8. Angles Right angle – has a square corner
Acute angle – less than a right angle
Obtuse angle – more than a right angle.
Straight angle – forms a straight line.

9. Lines Parallel lines – never intersect.
Intersecting lines – lines that cross through the same point.
Perpendicular lines – lines that form right angles where they intersect each other.

10. Quadrilaterals
Quadrilaterals can also be classified (or grouped) by their angles or their pairs of sides!
Remember , quad means 4! So we are talking about 4 sided figures!

11. Rectangle
Rectangle – there are 4 right angles!

12. Square
Square – there are 4 right angles and all sides are the same length.

13. Trapezoid
Trapezoid – There is only one pair of parallel sides.

14. Parallelogram
Parallelogram – opposite sides are parallel.

15. Rhombus
Rhombus – opposite sides are parallel AND all 4 sides are the same length.

16. Congruent
Congruent – Same shape and same size. *If items are congruent, they are automatically similar. However, just because items are similar, doesn’t mean they are automatically congruent.

17. Slide (Translation)
Slide (translation) – moves a figure in a straight direction.

18. Flip (Reflection)
Flip (reflection) – a figure gives its mirror image.

19. Turn (Rotation)
Turn (rotation) – moves a figure around a point.

20. Similar
Similar – same shape, but may or may not have the same size! *If items are congruent, they are automatically similar. However, just because items are similar, doesn’t mean they are automatically congruent.

21. Symmetry
Symmetry – when a figure can be folded into two congruent halves. *Means one half can lay perfectly over the other half in an exact match.
line of symmetry