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WELCOME TO THE PYTHAGOREAN THEOREM

STUDENT OBJECTIVES
PREVIEW
HISTORY OF PYTHAGORAS
PYTHAGOREAN   THEOREM
VIRGINIA STANDARDS
PRACTICE PROBLEMS
RESOURCES/LINKS
WORD PROBLEMS
FAVORITE LINKS
EVALUATION

 
 
Egyptian Pyramids
    Egyptian Numbers

Student Objectives:

Virginia Standards of Learning:
 

Preview:

The purpose of the three lessons(3-5 days) is for students to develop an understanding on how and why the Pythagorean Theorem works.

Lesson:

Lesson 1(History of Pythagoras)
 
 
Pythagoras of Samos(584B.C.-495BC.) was born in Samos, Greece.  His travels took him to Egypt and Babylonia where he became acquainted with the Egyptian and Babylonia mathematicians.  He settled in Crotona, a town of Dorian in Southern Italy.  His teacher Thales(known as the father of Greek mathematics)stirred his mind in the field of mathematics.  Thales ideas were formed from the lines cast by the shadows from the sun of the pillars across the pavement.  Figured numbers formed the significance in Pythagorean arithmetic.  Figured numbers include triangular numbers, square numbers, pentagonal numbers and irrational numbers.  Pythagorous drew attention to other mathematical terms such as parabolas, ellipses and hyperbole.  Pythagoras is best known as a geometer for his famous theorem that the square of the hypotenuse of any right triangle equals the sum of the squares of the other two sides.

 
 
 
 
 
 

Pythagorean Theorem Proof:
 

The parts of a right triangle that form the right angle are called the legs.  The part of the right triangle which stretches and connects the two legs is called the hypotenuse.


 
Given:  is a right angle.
Prove: 
Proof:
Statements
Reasons
1.Draw a perpendicular line from C to AB. 1. Through a point outside a line, one line can be drawn  perpendicular to the given line
2.  2.The altitude drawn to the hypotenuse of right triangle is the geometric mean between the hyp. and the seg. of the hyp. that is adjacent to the leg.
3.  ce = ; cd =  3.  A property of proportion
4.  ce + cd = 4.  Addition Property of Equality
5.  c(e + d) = 5.  Distributive Property
6.  6.  Substitution
*Houghton Mifflin Company, Jurgensen, Brown,  Jergensen,1992

 
 
 
 
 
 
 

EXAMPLES:


 
 
AB = 3, BC = 4 then AC = 5
 9   +  16  =  25
          25 =   25
 AB=6, BC=8  then  AC=10

36 +  64  =  100
100   =  100

Try the following problems.

AB= 3, BC= 7 then  AC=_____.

AB= 12, BC = 5 then AC =________.
 

BC= 30 , AB = 40, then AC=_______.

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