1.5, 2.3, 3.1, 3.9, __
4.3
4.5
4.7
4.9
5.02
In this simple addition series, each number increases by 0.8.
In a triangle ABC, BC ||DE If AD=1.5, DB=4.5, AE=1.3, EC=?
The volume strength of 1.5 N H2O2 is