Expert: Ahmed Salami - 11/30/2008

Question
The measure of each interior angle of a regular  polygon is 20 degrees more than three times the measure of each exterior angle.How many sides does the polygon have?

Answer
Hi Faiqa,
Each interior angle of a regular polygon with n sides is
(180/n)(n-2)
The exterior angle to it 360/n
From the information provided,
(180/n)(n-2) = 3(360/n) + 20
180 - 360/n = 1080/n + 20
180 - 20 = 1080/n + 360/n
160 = 1440/n
n = 1440/160
 = 9

Regards