Maths Question (Simple)

[Kaelaroth]

This is really, really easy:
Find the number of sides in a regular polygon with interior angle of 140 degrees.

HELP! Although it's easy, I appear to be damned stupid. :smallwink:

[KingRexII]

http://www.mathwords.com/a/area_regular_polygon.htm

Use this one:
Interior angle = 180(n-2)/n, and solve for n.

[Totally Guy]

Well if the internal angle is 140 then the angle that you'd need to turn through to continue the path from a straight line is 40.


_________

^Straight line. You're walking along it. And decide to turn 40 degrees. Then the internal angle of the line you are walking is 140.

To make a regular polygon you'd be walking alang the same distance then turn 40 again. etc etc.

By the time you are back where you started you'll have turned through 360 degrees. Like a circle.

So how many times did you turn? (As nr of corners = nr of sides... )

You travelled through 360 degrees, turning 40 each time.

360/40 = 9 times.

So you've made a shape with 9 sides.

[Cobra_Ikari]

9. >.>

I think?

[Shishnarfne]

Well, the total number of degrees of the internal angles for any polygon is (N-2)*180, so for your case you need simply to solve 140=(N-2)*180/N

140=(N-2)*180/N
140*N=180*N-360
360=40*N
N=9

Edit: And the ninjas are out in force today...