[{"data":1,"prerenderedAt":25},["ShallowReactive",2],{"content-rule-of-three-en":3},{"about":4,"steps":7,"faq":12},[5,6],"The rule of three is one of the most useful calculation methods in everyday life: from three known values, a fourth is calculated. If 3 kg of apples cost 7.50, how much do 5 kg cost? The method goes from the known pair to a single unit and from there to the quantity you are looking for.","The calculator solves both variants: direct proportion (“more → more”, e.g. quantity and price) and inverse proportion (“more → less”, e.g. number of workers and days needed). It shows the complete calculation path with your units – handy for homework, recipes, shopping or estimates. For percentages, use the [[percent-calculator]].",[8,9,10,11],"Choose whether the relation is proportional or inverse.","Enter the known pair, e.g. “3 kg correspond to 7.50 €”, and optionally the units.","Enter the quantity whose value you are looking for.","Read the result and the three-step calculation.",[13,16,19,22],{"q":14,"a":15},"How do I know whether it is proportional or inverse?","Ask yourself: if one quantity grows, does the other grow too? Then it is proportional (more goods cost more). If the other shrinks, it is inverse (more helpers need less time).",{"q":17,"a":18},"What is the formula?","Proportional: x = b ÷ a × c. Inverse: x = a × b ÷ c. For 4 workers needing 6 days, 3 workers need 4 × 6 ÷ 3 = 8 days.",{"q":20,"a":21},"Does the rule of three always apply?","Only if the relation really is (inversely) proportional. Volume discounts, base fees or group effects break it – then the result is only an approximation.",{"q":23,"a":24},"Can I convert units too?","For conversions between units such as km and miles or °C and °F, use the [[unit-converter]].",1792082296388]