If ABCDE is a regular pentagon and diagonals EB and AC intersect at O, then what is the degree measure of angleEOC?

Question

anonymous · Answer

|dw:1350441129403:dw|

hartnn · Answer

using the property that diagonals of regular pentagon trisect all the interior angles, we get 
angle OAB = OBC = 36 degrees (108/3, angle A=angle B =108 degrees)
now can u find EOC ?

hartnn · Answer

by first finding AOB

anonymous · Answer

Can you explain further? Sorry I can't understand :3

hartnn · Answer

diagonals of regular pentagon trisect all the interior angles
so, 
angle ABO will be 1/3 times interior angle ABC
so, angle ABO = 36 
similarly angle BAO = 36

so angle AOB will be 180 -36-36
(because angle in a triangle sum upto 180)

and since EOC is vertical to AOB
EOC = AOB

anonymous · Answer

how do you know that the interior angle of ABC is 108?

anonymous · Answer

how do you find the angle A is 108 as well as the angle B?
sorry I'm confused

anonymous · Answer

So EOC is 108?

hartnn · Answer

yes