TI-84 Plus and Silver Edition Manual

Activities 73

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, pr

Consider the formula A = NB

sin(pàN) cos(pàN) 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  0 to select 0: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=ANNB

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.

N = 4 sides

N = 8 sides

N = 12 sides