A few days ago
Anonymous

# Polygon questions? Math/ Geo. =[ help?

If the sum of the interior angles of a polygn is 1800 degrees, how many sides does the polygon have?

I did:

1800=(n-2)180

1800=180n-360

2160=180n

12=n

^ is that correct?

and

each interior angle of a regular polygon measures 140 degrees. How many sides does the polygon have? Ex. ur answer.

i tried doing the same thing (equation) as the previous question but i got a decimal??

A few days ago
۞_ʞɾ_۝

“each interior angle of a regular polygon measures 140 degrees. How many sides does the polygon have?”

the total degree of all exterior angles of a regular polygon is always 360. if the interior angle is 140, then its exterior must be 40. so 360/40=9 sides.

to find how many sides if you have 1 known interior angle. you use, 360/(180-x), where x is the degree of the given interior angle.

the 1st one looks correct. doubt check it, 12 sides, 1800/12=150 degree. that means each interior angle is 150. and if the interior angle is 150, the exterior must be 30. 360/30=12 sides. so its correct

3

A few days ago
Wylie Coyote
1 is correct. You did it in reverse? 140,280,420,560 use a different formula for the second half. Number of sidesx140=(n-2)180.

140n=(n-2)180

N=9.

0

A few days ago
dbu_44240
yes, correct.