Answer :

naǫ
x - the number

[tex]80\%x=12 \\ \frac{80}{100}x=12 \\ \frac{4}{5}x=12 \\ x=12 \times \frac{5}{4} \\ x=3 \times 5 \\ x=15[/tex]

12 is 80% of 15.
12 is 80% of 15 
hope i helped