Texas Instruments TI-83-Plus - Page 40

Chapter 1: Number Sense Name
Section 3: Real Numbers Date
Topics in Algebra 1 © 2001 Texas Instruments Student Worksheet 1-26
³
Try-It!
é
on Your TI
.
83 Plus or TI
.
73
Investigate how the calculator deals with irrational numbers.
In the
Overview
, you used the Pythagorean theorem to find the length of
À
2
. Draw a right
triangle so that the hypotenuse has length
À
2
. Pythagoras (569–475
B
.
C
.), a great Greek
mathematician, discovered irrational numbers (numbers that are not rational and therefore are
not ratios). There is a proof that, for example,
À
2
cannot be written as a fraction.
Hint:
Draw each leg with length 1 inch. The hypotenuse is
Á
1
2
+1
2
=
À
1+1 =
À
2
Remember that
À
2
Q
À
2
=
2
. Picture this by envisioning a square whose sides measure
À
2
units.
You created this length in your picture above.
Look at the square whose side has a length of
À
2
on the Geoboard screen below. Can you see
that the area is
À
2
Q
À
2
=
2
square units? Count it up! Shade in the area on the screen shown.
From the TI
-
73 Geoboard
application