Download GEOMETRY REVIEW Grades 5

GEOMETRY REVIEW
Grades 5 - 8
Point– a location in space
.
Line-- a straight path that goes on forever in both
directions.
Line segment– a straight path between 2 points,
called its endpoints.
A
B
• Ray– a straight path that goes on forever
in one direction from an endpoint.
• Angle– two rays of line segments with a
common endpoint, called the vertex.
Types of lines
• Parallel lines—lines that never meet and
are the same distance apart.
• Intersecting lines– lines that meet.
Types of Angles
• Acute angle measures between 0 and 90
degrees.
• Obtuse angle measures between 90 and
180 degrees.
Types of Angles
• Right angle measures 90 degrees.
• Straight angle measures 180 degrees.
POLYGONS
• A polygon is a flat 2-dimensional figure made up
of 3 or more line segments called sides.
• The sides of a polygon are connected end-toend and make a closed figure.
• Each endpoint where two sides meet is called a
vertex. The plural of vertex is vertices.
REGULAR POLYGONS
• A regular polygon is a polygon whose
sides all have the same length and whose
angles are all the same size.
• We say that a regular polygon is both
equilateral and equiangular.
NAMES OF POLYGONS
• Polygons are named according to the number
of sides.
•
•
•
•
•
3 sides--triangle
8 sides--octagon
4 sides--quadrilateral 9 sides--nonagon
5 sides--pentagon
10 sides--decagon
6 sides--hexagon
12 sides--dodecagon
7 sides--heptagon
QUADRILATERALS
Parallelogram
Trapezoid
(2 pair of parallel sides)
(opposite sides are congruent)
(diagonals bisect each other)
(opposite angles are congruent)
Rectangle
(properties of parallelogram
and has 4 right angles)
(diagonals are congruent
(1 pair of parallel sides)
Rhombus
(properties of parallelogram and
has all sides are congruent)
(diagonals are perpendicular)
Square
(properties of parallelogram,
has 4 right angles, all sides are congruent)
(diagonals are congruent, diagonals are perpendicular)
GEOMETRIC SOLIDS
… are 3-dimensional figures.
The flat surfaces of the solid are called
faces.
The faces of the solid meet to form line
segments called edges.
The corners of a solid are called vertices.
EDGES = Faces + Vertices - 2
POLYHEDRONS
• A polyhedron is a geometric solid whose
surfaces are formed by polygons.
• The faces of a polyhedron are all
polygons.
• A polyhedron does not have any curved
surfaces.
• A polyhedron is regular if all of its faces
are the same size and shape.
REGULAR POLYHEDRONS
• Tetrahedron…has 4 faces of equilateral
triangles (also called a pyramid)
• Cube…has 6 faces of squares (also called
prism)
• Octahedron…has 8 faces of equilateral
triangles
• Dodecahedron…has 12 faces of regular
pentagons
• Icosahedron…has 20 faces of equilateral
triangles
AREA
• Area is the amount of surface inside a shape.
Area is measured in square units such as
square inches or square centimeters.
• Area of a parallelogram = base x height
• Area of a rectangle = base x height
or length x width
• Area of a triangle = base x height
2
• Area of a circle = 3.14 x radius x radius
PERIMETER
…..is the distance around a shape.
The perimeter is the sum of all the sides.
4 cm
3 cm
3 cm
4 cm
Perimeter = 4 cm + 3 cm + 4 cm + 3cm
Perimeter = 14 cm
METRIC PREFIXES
• Kilo Hecto Deca m Deci Centi Milli
l
g
King Henry Died……… Drinking Chocolate Milk.
To change from one measure to another, simply move the
decimal point to the right or left.
METRIC MEASURES
• For length use meters, etc.
• For weight (mass) use grams, etc.
• For volume use liters, etc.
Metric Measures
• A meter is slightly longer than one yard.
1 meter is about 39.37 inches
1 inch is about 2.5 centimeters
1 kilometer is about 0.6 mile
1 mile is about 1.6 kilometers
• A liter is slightly more than one quart.
1 liter is about 1.1 quarts
• A gram is about the weight of one paper clip.
1kilogram is about 2.2 pounds.