David and his family went out to eat in the bill was $80 and he gave the waiter 30% how much was did he give the waiter

Sherrie is baking a pie for her family. she leaves the room and comes back to 35% of the pie having been eaten before she can put the topping on. how much 1 square inch strips of dough will she need for the top, now that a portion is missing? round your answer to the nearest while nimber.