Joan is making a picture frame in the shape of a regular decagon. What should be the measure of each of the interior angles of joan's frame?

Question

anonymous · Answer

36?

anonymous · Answer

it says that the answer is wrong and to use the formula (n-2)180/n

campbell_st · Answer

the angle sum of any polygon is 

Angle Sum = 180 x (n -2)                n = the number of sides.

in you question you need substitute n = 10   as a decagon has 10 sides. 

when you have the angle sum divide by 10, this will give the size of 1 angle in a regular decagon. 

Which is also the size of 1 angle

anonymous · Answer

sorry i made a mistake,u r right

campbell_st · Answer

the answer posted by @sorour is almost correct. 

The exterior angles in every polygon sum to 360 

so in a regular decagon, 1 exterior angle is 36 degrees. 

to find the interior angle find the angle that is supplementary to 36.

anonymous · Answer

Okay I think I understand now, Thanks