Question

Suppose a regular n-gon is inscribed in a circle of radius r. Diagrams are shown for n=6, n=8, and n = 12. n = 6 n=8 n = 12 a a VT a Imagine how the relationship between the n-gon and the circle changes as n increases. 1. Describe the relationship between the area of the n-gon and the area of the circle as n increases.​

Answer 1

Answer:If an N-gon (polygon with N sides) has perimeter P, then each of the

N sides has length P/N. If we connect two adjacent vertices to the

center, the angle between these two lines is 360/N degrees, or 2*pi/N

radians. (Do you understand radian measure well enough to follow me

this far?)

The two lines I just drew, plus the side of the polygon between them,

form an isosceles triangle. Adding the altitude of the isosceles

triangle makes two right triangles, and we can use one of them to

derive the equation

sin(theta/2) = s/(2R)

where theta is the apex angle (which I said is 2*pi/N radians), R is

the length of the lines to the center (the radius of the circumscribed

circle), and s is the length of the side (which I said is P/N).

Putting those values into the equation, we have

sin(pi/N) = P/(2NR)

so that

P = 2NR sin(pi/N)

gives the perimeter of the N-gon with circumradius R.

Can we see a connection between this formula and the perimeter of a

circle? The perimeter of the circumcircle is 2*pi*R. As we increase

N, the perimeter of the polygon should get closer and closer to this

value. Comparing the two, we see

2NR*sin(pi/N) approaches 2*pi*R

N*sin(pi/N) approaches pi

You can check this out with a calculator, using big numbers for N such

as your teacher's N=1000. If you calculate the sine of an angle in

degrees rather than radians, the formula will look like

N*sin(180/N) --> pi

Explanation: