Answer:
Option 4 is not true
Step-by-step explanation:
[tex]\frac{a}{b}=\frac{c}{d}\\\\[/tex]
1)Cross multiply,
ad = bc
So, true
2) a/ c = b/d also true
3) a+b/b = c+d/d also true
For example:
[tex]\frac{1}{4}=\frac{2}{8}\\\\\frac{1+4}{4}=\frac{2+8}{8}\\\\\frac{5}{4}=\frac{10}{8}\\\\[/tex]
When simplifying 10/8, it is 5/4.
5) b/a = d/c is also true