GEOMETRYSHAPES
TRIANGLE
TRIANGLE – 3 SIDED SHAPE TRI MEANS 3
TRIcycle (3 wheels)
TRIlogy (3 books in the series)
(3 Horns)
QUADRILATERAL
A quadrilateral is a polygon with 4 sides. These are all quadrilaterals:
“QUAD” MEANS 4
Quadriceps – 4 muscles
Quadrant – 4 sections
Quadruplets (4 babies)
PENTAGON
•A pentagon is a 5-sided shape.•“Pent” means 5
U.S. Pentagon in Washington D.C.
Pentagram – 5 pointed star
HEXAGON
•A hexagon is a 6-sided shape•“Hex” means 6
Hexagram – 6-pointed star
HEX nut – six sided nut
(Ask Jacob)
Hexapod – 6 feet
HEPTAGON
•A heptagon is a 7-sided figure•“Hept” means 7
Heptathlon – 7 event competition Heptadactyly– 7 fingers on 1
hand
OCTAGON•An octagon is an 8 sided figure•“Octa” means 8
Octopus – 8 legs
Octamom!
Octogenarian – a person who is in there 80’s
NONAGON
•A nonagon is a 9-sided figure•From the Latin word “nonus” and the Greek word enneagonon, meaning 9
Enneagram – 9 personality types
DECAGON
•A decagon is a 10-sided shaped•“Deca” means 10
Decathalon – 10 track and field
events
Decade – 10 years
Decimal – base 10 number system
LET’S REVIEW
PENTAGON
heptagon
HEXAGON
NONAGON
OCTAGON
DECAGON
CLASSIFYING QUADRILATERALS
Quadrilateral – 4 sides, 4 angles, a type of polygon
Rectangle – opposite sides are congruent; has 4 right angles
Square – 4 congruent sides; 4 right angles
Parallelogram – opposite sides are congruent and parallel
Rhombus – 4 congruent sides; opposite sides are parallel
Trapezoid – only 1 pair of parallel sides
LET’S CLASSIFY
Polygon
Polygon
Quadrilateral Trapezoid
Quadrilateral
Parallelogram
LET’S CLASSIFY
Polygon Quadrilater
al ParallelogramRhombus
PolygonQuadrilater
al ParallelogramRhombus
RectangleSquare!
TRIANGLES
A triangle has 3 sides and 3 angles
TYPES OF TRIANGLES BASED ON HOW MANY SIDES AND ANGLES ARE EQUAL
An EQUILATERAL triangle has 3 equal sides and 3 equal angles (always 60 degrees)
An ISOSCELES triangle has 2 equal sides and 2 equal angles
An SCALENE triangle has NO equal sides and NO equal angles
TYPES OF TRIANGLES BASED ON TYPES OF ANGLES
An ACUTE triangle is a triangle with ALL angles less than 90 degrees.
A RIGHT triangle is a triangle with a 90 degree angle.
An OBTUSE triangle is a triangle with an angle of more than 90 degrees.
A TRIANGLE CAN HAVE TWO NAMES
isosceles right triangle
TRIANGLES
An equilateral triangle is always….ACUT
E
TRIANGLES
In a right triangle, one of the angles is a right angle—an angle of 90 degrees. A right triangle may be isosceles or scalene.
In an obtuse triangle, one angle is greater than a right angle—it is more than 90 degrees. An obtuse triangle may be isosceles or scalene.
In an acute triangle, all angles are less than right angles—each one is less than 90 degrees. An acute triangle may be equilateral, isosceles, or scalene.
YOUR TURN!
Draw each of the following:
1.Right isosceles triangle2.Obtuse scalene triangle3.An acute equilateral triangle
1.Right isosceles triangle
2. Obtuse scalene triangle
3. Acute equilateral triangles