An alcoholic strength of 42.8% v/v (volume/volume) means that in a given volume of liquid, 42.8% of it is pure alcohol (ethanol) and the remaining 57.2% is composed of other substances, usually water and some other minor compounds. This percentage represents the proportion of alcohol by volume in the total liquid.
For example, if you have 100 milliliters (ml) of a beverage with an alcoholic strength of 42.8% v/v, it means that 42.8 ml of that 100 ml is pure alcohol, and the remaining 57.2 ml is water and other components.
Alcoholic strength is commonly used to indicate the potency of alcoholic beverages such as spirits, liquors, and some types of alcoholic cocktails. Different alcoholic beverages have varying alcohol strengths, and it's important to be aware of these percentages to consume them responsibly.