## GEOMETRY

GEOMETRY VOCABULARY AND DEFINITIONS:

Perimeter-distance around a figure
Area of a rectangle= b x h
Area of a triangle= 1/2 (b x h)
Line segment
Line
Ray
Angles:  Acute, Straight, Obtuse, Right
Translation=slide
Reflection=flip
Rotation-Clockwise or counterclockwise
Symmetry
Triangles:  Equilateral (3 congruent sides), Isosceles (2 congruent sides), Scalene (no congruent sides)
Circumference-distance around a circular object
Diameter-a chord that passes through the center of a circle is a diameter.
Radius-a line segment with one endpoint at the center of a circle and the other endpoint on the circle
Circumference= 3.14 x diameter
Conversions:  see below  (Measurements)
SALAD-Small to Large, Divide  ie.) 24 inches (24 divided by 12) =2 ft.
LONESOME -Large to Small, Multiply  ie.) 3 yards (3 x 3) = 9 ft.

Polygons:
triangle "tri" means 3
pentagon  "pent" means 5
hexagon  "hex" means 6
octagon   "oct"  means 8
decagon   "deca" means10
polygon   "poly"  means many

SIMILAR-Two figures are similar if they have the same shape.  They do not have to be the same size.

CONGRUENT-Two figures are congruent if their corresponding sides and angles are equal.

TESSELATION-covers a surface with no gaps or overlaps

SOLID FIGURES:

PRISM-is a solid figure that has 2 congruent faces called bases.  A prism is named by the polygons that form its bases.  example:  hexagonal prism-faces are rectangles, bases are hexagons

Pyramid is a solid figure with one base that is a polygon and three or more faces that are triangles with a common vertex.  A pyramid is named by the polygon that forms its base.  example:  hexagonal pyramid  (faces are triangles, base is a hexagon)