B.ed File

1. TOPIC – PYTHAGORAS
THEOREM

2. This is a right angle triangle.

3. We call it a right triangle because it
contains a right angle

4. The measure of a right angle is 90°

5. The little square in the triangle tells you
it is a right angle.
90°

6. About 2,500 years ago, a Greek
mathematician named Pythagoras
discovered a special relationship
between the sides of right
triangles.

7. Pythagoras realized that if you have a
right triangle,
3
5
4

8. and you square the lengths of the two
sides that make up the right angle
3
5
4
32 42

9. And add them together,
5
4
3
32 + 42

10. You get the same number you would
get by squaring the other side.
5
4
3
32 + 42 = 52

11. Is that correct?
?
32 + 42 = 52
9 + 16 = 25

12. It is. And it is true for any right triangle.
10
8
6
62 + 82 = 102
36 + 64 = 100

13. The two sides which comes together in
a right angle are called legs.
b
a

14. The lengths of the legs are usually
called a and b.
a
b

15. The side across from the right is called
the hypotenuse.
a
b

16. And the length of the hypotenuse is
usually labeled.
a
b
c

17. The relationship Pythagoras discovered
is now called The Pythagoras Theorem.
b
c
a

18. The Pythagorean Theorem says, given
the right triangle with legs a , b and
hypotenuse c.
c
a
b

19. Then a2 + b2 = c2 .
c
a
b

20. Using the Pythagoras Theorem we
can solve many problems. If a
persons walks 48 m from East to
West.
48

21. The turn south and then turns south
and walks for 36 m to the south.
48
36

22. How far he is from where he started?
48
36
?

23. Using the Pythagorean Theorem,
48
36
c
482 + 362 = c2

24. Then all we need to do is calculate;
482 + 362 = 2304 + 1296
3600 = c2
Therefore c = 60 m