Internal Septagon

Geometry Level 1

A septagon is a figure with 7 sides. What is the sum of internal angles (in degrees) of a septagon?


The answer is 900.

View wiki
Arron Kau by Arron Kau

This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try refreshing the page, (b) enabling javascript if it is disabled on your browser and, finally, (c) loading the non-javascript version of this page . We're sorry about the hassle.

11 solutions

Sum of internal angles = 180 (n-2), where n is number of sides 180 (7-2) = 180 (5) = 900

2 Helpful 0 Interesting 0 Brilliant 0 Confused
Ted van Ryn
Aug 12, 2013

Sum of internal angles of a polygon is given by (n-2) x 180 degrees where n is the number of sides of the polygon.

For a septagon, n=7, then the sum of internal angles is (7-2)x180 = 5x180=900.

1 Helpful 0 Interesting 0 Brilliant 0 Confused
Siraz Shaikh
Mar 30, 2014

we can say that sum of interior angles is 180 times no of triangles as each triangle contributes 180 degrees

0 Helpful 0 Interesting 0 Brilliant 0 Confused
Rakhmat Muliawan
Aug 17, 2013

I write with Indonesian: segi n = (n - 2) x 180 segi 7 = (7 - 2) x 180 = 5 x 180 = 900

0 Helpful 0 Interesting 0 Brilliant 0 Confused
Imad Fatimy
Aug 17, 2013

So here i've used A formula wich is : Sum of Interior Angles = (n-2) × 180° ans n is the number of sides so : Sum of Interior Angles = (7-2) × 180° = 5 × 180 = 900

0 Helpful 0 Interesting 0 Brilliant 0 Confused
Austin Lloyd Aspa
Aug 17, 2013

If the sum of internal angles of a triangle is 180 degrees

And there are 5 triangles in a septagon therefore

(180)5=900

0 Helpful 0 Interesting 0 Brilliant 0 Confused
Aniebiet Akpan
Aug 15, 2013

the formula is simple, (n-2)180=total number of internal angles of an polygon, therefore for septagon or hetagon= (7-2)180=900. simple!

0 Helpful 0 Interesting 0 Brilliant 0 Confused
Márko Sálcedo
Aug 14, 2013

(7-2)x(180) =900

0 Helpful 0 Interesting 0 Brilliant 0 Confused

sides-n = (n-2) x 180 degrees = (7-2) x 180 degrees = 900 degrees

0 Helpful 0 Interesting 0 Brilliant 0 Confused

Sn = (n - 2)180; Sn = (5)180; Sn = 900º

0 Helpful 0 Interesting 0 Brilliant 0 Confused
Nelvson Shine
Aug 11, 2013

To find a internal ( or sometimes its called " interior " ) angles, the formula is :

= ( n − 2 ) ∗ 180 (n - 2) * 180

where n is the total sides. Then we replace "n" with 7, so the internal angles is :

= ( 7 − 2 ) ∗ 180 (7 - 2) * 180

= 5 ∗ 180 5 * 180

= 900 900

Thus the answer is 900.

0 Helpful 0 Interesting 0 Brilliant 0 Confused

Moderator note:

Can you give a quick explanation of how to arrive at this formula? There are numerous proofs of this fact.

Thanks for using an important short formula in this case to solve the sum of internal angles of a polygon.

Tamanna Zinia - 7 years, 10 months ago

why do we have to subtract 2 from the total sides of a shape ? Because there is no "two sides shape". at least we need 3 sides.

Why do we have to multiply 180 ?

The "minimum requirement" something could call a shape is at least its need 3 sides. a three-sides shape usually called triangle. in a triangle we obviously know that the interior angles are 180. 180 its a quite big number, since after ( 3 - 2 ), suddenly we have to add something on our formula, so have to conclude that we should multiply a variable, just say that variable called t h e t a theta

(triangle total sides - 2 ) * t h e t a theta = 180

3 − 2 3 - 2 * t h e t a theta = 180

t h e t a theta = 180

from that maybe we can make the formula how to find out a interior angle of a shape : = ( n − 2 ) ∗ 180 ( n - 2 ) * 180

hope you understand

Nelvson Shine - 7 years, 10 months ago

Log in to reply

heaven, i thought that "theta" would appear like this θ \theta . my bad.

Nelvson Shine - 7 years, 10 months ago

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...