If the sum of interior angle measures of a polygon is 900, how many sides does the polygon have?

the polygon is *heptagon (7-sided polygon)

Sum of interior angles is ##180(n-2)##

Since sum is ##=900##,

##900=180(n-2)##

##900/180=(180(n-2))/180##

##900/180=(cancel180(n-2))/cancel180##

##5=n-2##

##5+2=n##

##7=n##