If the sum of the measures of the interior angles of a convex polygon is 2160°, how many sides does the polygon have? 6 sides 18 sides 14 sides 16 sides

When george started his current job, his employer told him that at the end of the first year, he would receive two vacation days. after each year worked, his number of vacation days will double up to five work weeks (25days) of payed vacation. how many vacation days will he have in 4 years