Doing a test I am in 6th grade but I just don’t know this answer someone plz help

Hello, i need compare km^2 and km. what's difference in this?

The table below shows the number of free throw shots attempted and the number of shots made for the five starting players on the basketball team during practice. each player's goal is to make 80% of her shots. players number of free throws made free throw attempts kelly 16 20 sarah 25 30 maggie 31 40 liz 44 50 kim 47 60 how many players made at least 80% of their shots? round to the nearest percent.

Whoever gets this right gets the ! the half life of a soul smelling substance is 4 years. if you have 8 oz of this strange substance, how much of it will you have after 20 years? show work.