Homework Help

I'm not sure about this question... The measure of an exterior angle of a regular n-gon...

user profile pic

tjjavid | Student, Undergraduate | Honors

Posted April 23, 2013 at 5:33 AM via web

dislike 0 like

I'm not sure about this question...

The measure of an exterior angle of a regular n-gon is 72 degrees. classify the polygon by number of sides.

I think it's a heptagon but i'm not sure it might be a pentagon.

2 Answers | Add Yours

user profile pic

pramodpandey | College Teacher | Valedictorian

Posted April 23, 2013 at 5:52 AM (Answer #1)

dislike 0 like

Each interior angle of n regular polygone is

`angle s=((n-2)xx180)/n`       (i)

since exterior angel of given polygone is `72^o`

`` Therefore corresponding interior angle is =`180-72=108^o`

substitute 108 in (i) ,we have

`108=((n-2)xx180)/n`

`108n=180n-360`

`360=72n`

`n=72`

Polygone has 72 sides.

user profile pic

tjjavid | Student, Undergraduate | Honors

Posted April 23, 2013 at 6:51 AM (Answer #2)

dislike 0 like

Each interior angle of n regular polygone is

       (i)

since exterior angel of given polygone is

Therefore corresponding interior angle is =

substitute 108 in (i) ,we have

Polygone has 72 sides.

You did not say if it's a heptagon or pentagon.

Join to answer this question

Join a community of thousands of dedicated teachers and students.

Join eNotes