Chapter 17: Activities
321
5. Press
r
. Notice that although the three graphs defined by
Y5
are different, they share the
same derivative.
N = 4 sides
N = 8 sides
N = 12 sides
Computing Areas of Regular N-Sided Polygons
Problem
Use the equation solver to store a formula for the area of a regular N-sided polygon, and then
solve for each variable, given the other variables. Explore the fact that the limiting case is the area
of a circle,
p
r
2
.
Consider the formula A = NB
2
sin(
pà
N) cos(
pà
N) for the area of a regular polygon with N sides of
equal length and B distance from the center to a vertex.
Procedure
1. Press
t
B
to select
B:Solver
from the
MATH
menu. Either the equation editor or the
interactive solver editor is displayed. If the interactive solver editor is displayed, press
}
to
display the equation editor.
2. Enter the formula as
0=A
N
NB
2
sin(
p
/ N)cos(
p
/ N)
, and then press
Í
. The interactive solver
editor is displayed.
3. Enter
N=4
and
B=6
to find the area (
A
) of a square with a distance (
B
) from center to vertex of
6 centimeters.
4. Press
} }
to move the cursor onto
A
, and then press
ă \
. The solution for
A
is
displayed on the interactive solver editor.
