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let y be the angle
144 less than y less than 150

( n - 2 )x 180 = yn
( n - 2 )x 180 / n = y
144 less than ( n - 2 )x 180 / n less than 150
144n less than 180n - 360 less than 150n
144 less than 180 - 360/n less than 150
-36 less than -360/n less than -30
36 more than 360/n more than 30
1/10 more than 1/n more than 1/12
10 less than n less than 12
therefore n = 11

用大於小於符號(箭嘴)會自動變成代號 所以不用了

All angles are the same in a regular polygon
angle sum of polygon = (n-2)180
each angle = [(n-2)180] / n

144 smaller than [(n-2)180]/n smaller than 150

[(n-2)180]/n greater than 144
180n -360 greater than 144n
180n -144n greater than 360
36n greater than 360
n greater than 10

[(n-2)180]/n smaller than 150
180n-360 smaller than 150n
180n-150n smaller than 360
30n smaller than 360
n smaller than 12

10 smaller than n smaller than 12
and n is an integer

therefore n = 11