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? asked in Education & ReferenceHomework Help · 8 years ago

How do you find exterior/interior angles in polygons?

My maths homework is confusing me, and we haven't even done this in class yet! Please explain how you;

-Find exterior angles in a polygon

-Find interior angles

-Find the number of sides from the angle sizes?

I have no idea please help??

(btw - these are the questions:

1. A regular polygon has 29 sides. Find the size of each interior angle.

2. Each exterior angle of a regular polygon is 36o. How many sides?

3. The sum of the interior angles of a polygon is 4500o. How many sides?

3 Answers

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  • Anonymous
    8 years ago
    Favorite Answer

    For a regular polygon.

    - Sum of exterior angles = 360

    Formula for an individual exterior angle ---> 360 / n

    - Sum of Interior Angles = 180(n - 2)

    Individual Interior Angles = 180(n - 2) / n

    1) n = 29

    Individual Interior Angles = 180(n - 2) / n

    = 180(29 - 2) / 29 = 167.6°

    2) Individual exterior angle ---> 360 / n

    36 = 360 / n ---> n = 360 / 36 = 10 sides.

    3) Sum of Interior Angles = 180(n - 2)

    4500 = 180n - 360 ---> 180n = 4860

    n = 27 sides

  • 8 years ago

    The sum of the interior angles of a polygon is S-2 (180) where S is the number of sides.

    1.) (29 - 2) (180) = 27 * 180 = 4860 degrees

    http://www.mathopenref.com/polygoninteriorangles.h...

    2) The sum of the exterior angles of a polygon is always 360 degrees

    since the polygon is regular all angles are the same

    360/S = 36 ; S = 360/36 = 10 sides

    http://www.mathopenref.com/polygonexteriorangles.h...

    3 as in question 1 number of sides = N

    (n-2)(180) = 4500 ; n-2 = 4500/180 = 25 ; n = 25 +2 = 27 sides

  • ?
    Lv 4
    5 years ago

    Extrrior angles add up to 360, which is fairly handy to prove. Imagive going for walks along such exterior angles. You can at one in all them, and then you possibly can walk around, finally you have got ended up where you could have began. As a result, you will have accomplished a 360 rotation. Additional facet notes is that each exterior perspective is a hundred and eighty - z which z is the perspective meavsure of a normal polygon. We all know that z in comparative with the number of aspects yiels (n-2)180/n. So, we have n(180-one hundred eighty(n-2)/n) => 180n(1-(n-2)/n) = 180n([n-(n-2)]/n) = 180(n-(n-2)) = one hundred eighty(2) = 360. Oh an ingeneral, sum of interrior angles is a hundred and eighty(n-2) the place n is the number of facets ;)

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