we have that
A ratio is an ordered pair of numbers a and b, written a / b where b does not equal 0
and
A proportion is an equation in which two ratios are set equal to each other
example
[tex]\frac{a}{b}=\frac{c}{d}[/tex]the procedure to solve a proportion is
step 1
Multiply in cross
so
[tex]a*d=b*c[/tex]step 2
solve for the desired variable
example: solve for variable a
[tex]a=\frac{b*c}{d}[/tex]