1. Triangle Vocabulary Equilateral:
A triangle with three sides with equal lengths
Isosceles:
A triangle with two sides of equal length
Scalene:
A triangle with no equal sides

2. Triangle Vocabulary Acute Triangle: A triangle with three acute angles
Obtuse Triangle:
A triangle with one obtuse angle
Right Triangle:
A triangle with one right angle

3. Quadrilateral Vocabulary
Polygon:
A closed figure with at least three sides
Quadrilateral:
A four sided figure
Parallelogram:
Two pairs of parallel sides and two pairs of congruent sides

4. Quadrilateral Vocabulary
Rectangle:
Four right angles
Rhombus:
Four congruent sides
Square:
Four right angles and four congruent sides
Trapezoid:
One pair of parallel sides

5. Polygon Vocabulary Polygon: A closed figure with at least three sides
Triangle:
A three sided polygon
Quadrilateral:
A four sided polygon
Pentagon:
A five sided polygon

6. Polygon Vocabulary Hexagon: A six sided polygon Heptagon (Septagon)
A seven sided polygon
Octagon
An eight sided polygon
Nonagon
A nine sided polygon
Decagon
A ten sided polygon

7. Polygon Vocabulary Congruent: Equal Regular:
All sides and angles of a polygon are congruent
Diagonal:
A line joining two nonconsecutive vertices of a polygon