Transcript “Will I Ever Use This Stuff?”

Warm-Up Exercise
4–5
4 – (-5)
-4 – 5
-4 – (-5)
(4 – 5)2
(-4 – 5)2
-(4 – 5)2
-(-4 – 5)2
Opening Task
• Take a couple of minutes and see if you
can think of an example of geometry in:
– Nature
– Architecture
– Sports
– Your Home
– In this Classroom
What Did You Come Up With?
– Nature
– Architecture
– Sports
– Your Home
– In this
Classroom
– Any others?
Nature
Architecture
Art
Navigation
Biology
Chemistry
Engineering
Sports and Games
And of course …
You Might Be Surprised
Why Study Geometry?
• It is like detective work.
• It trains your mind to think in a logical fashion
and develop creative solutions to problems.
• It just might be the most valuable course you
ever take.
• It is a big part of the SAT and ACT tests. You can
count on about 40% being Geometry.
History
• Where does the word geometry come
from?
• The subject began when people began to
take notice of shapes of objects that occur
in nature. Can you think of examples of
these things in nature?
– Points, straight lines, parallel lines
– Angles
– Circles, spheres
– Cylinders
Examples in Nature
– Points: Stars
– Lines: Fingers, tree branches, blades of grass,
spiders web, layers inside rocks, falling rain, tall trees
– Angles: Arm bent at the elbow, crossing paths in a
field, changing direction of a shadow
– Circle/spheres: Moon, sun, eyeball, cross sections of
fruits, animal tied to a stake in the ground
– Cylinders: tree trunk
– Complicated figures: snowflakes, honeycombs, spider
webs.
History
• Used by ancient Babylonians, Egyptians,
Romans and Greeks in practical applications
– Land measurement, Surveying, Construction
– Navigation, Astronomy
• Organized by the Greeks between 600 and 300
BC
– Put together by Euclid in his famous book Elements
• Used logic and reasoning and the tools of axioms,
postulates, definitions, theorems and constructions to prove,
describe, calculate, generate or use information pertaining to
geometric objects.
What Will We Be Studying?
• Plane geometry: The study of squares,
rectangles, circles and other combinations
of points and lines that lie on a plane
surface.
• Solid geometry: The study of solid figures
such as cubes, cylinders and spheres.
Homework
• Get a protractor and compass.