Is every whole number an integer? is every integer a whole number?

1. what are the missing reasons in the proof 2. it's in the second picture and 3

Find the area of the regular hexagon if a side is 20 cm.

The u-drive rent-a-truck company plans to spend $13 million on 320 new vehicles. each commercial van will cost $25 comma 000, each small truck $50 comma 000, and each large truck  $80 comma 000. past experience shows that they need twice as many vans as small trucks. how many of each type of vehicle can they buy?