When they are equivalent ratios.
If two ratios have the same value when simplified.
Two ratios, a/b and c/d have the same value is a*d = b*c. A ratio, a/b, is said to be simplified if a and b are co-prime.
Two ratios are equivalent if their simplest forms are the same.
Equivalent ratios are ratios which have the same value when simplified. For example: The two ratios 8 : 24 and 4 : 12 are equivalent, because when simplified they are both 1 : 3 Hope this helps! :)
One to two Two to four They're known as equivalent ratios.