## anonymous one year ago Find the measure of each exterior angle of a regular dodecagon.

1. anonymous

okay well do you know what a dodecagon looks like

2. anonymous

yes, 12 sides correct?

3. anonymous

yes

4. anonymous

okay

5. anonymous

pls help

6. anonymous

dont actually have a clue how to do this but here http://www.coolmath.com/reference/polygons-12-dodecagons

7. AakashSudhakar

There is a master equation to find the interior angle measure of any regular polygon. That equation is as follows: $180^{o}(N-2) = \theta$where theta is your internal angle measure and N is the number of sides that the polygon has. To find the external angle measure corresponding to any internal angle measure, recall that for any polygon, the bounded internal and external angle measures sum up to 360 degrees. Therefore, to find an external angle measure, simply subtract the equation above's value from 360 degrees for a regular dodecahedron.

8. AakashSudhakar

I'm sorry, I messed up a little. The equation above gives the TOTAL degrees contained by any polygon. You have to divide that number by N to get an individual internal angle measure. Then subtract that value from 360 to get an external angle measure.

9. anonymous

is it 15?

10. anonymous

well by just looking at the figure you know its more than 90

11. anonymous

it should be 150

12. anonymous

|dw:1438282763254:dw|

13. anonymous

The options are A. 15 degrees, B. 60 degrees, C. 30 degrees and D. 20 degrees

14. anonymous

so whats 180 + 30

15. anonymous

oh okay im wrong then

16. anonymous

are you sure its asking for the exterior angle?

17. anonymous

yes

18. anonymous

thats strange im positive the interior angle is 150

19. anonymous

exterior

20. anonymous

well yea thats what i just did in the picture, and i'm sort of certain exterior angles have to be more than 180 so perhaps it means how much greater than 180 (which is a given) the angle is. In this case 30. what do you think?

21. anonymous

yes thank u so much

22. anonymous

Exterior angles always total 360 degrees regardless of the number of angles.