Bruce is getting materials for a chemistry experiment. his teacher gives him a container that holds 0.25 litter of a blue liquid. bruce needs to use 0.4 of this liquid for the experiment. how much blue liquid will bruce use?

So he has 0.25 liter of liquid or 25/100 or 1/4 L of liquid

he wants to use .4 or 4/10 or 2/5 of the blue liquid or
he wants to use 2/5 of 1/4 L
so we can read 'of' as multiply and multiply 2/5 and 1/4 and get
2/20 or 1/10 Liter he will use

Also, why the attachement?

Arhombus is a quadrilateral.