Using a Proportion

Property Set up a proportion where one ratio compares the part to the whole, and the other ratio is the percent rate written in the form of a ratio. Then, solve for the unknown. $$ \frac{\text{part}}{\text{whole}} = \frac{\text{percent}}{100} $$.

Examples What number is 120% of 50? Answer: $\frac{c}{50} = \frac{120}{100} \rightarrow 100c = 6000 \rightarrow c = 60$ 20 is what percent of 80? Answer: $\frac{20}{80} = \frac{x}{100} \rightarrow 80x = 2000 \rightarrow x = 25$ 30 is 60% of what number? Answer: $\frac{30}{x} = \frac{60}{100} \rightarrow 60x = 3000 \rightarrow x = 50$.

Explanation Set up a super fair trade! One fraction is the part over the whole, and the other is the percent over 100. Cross multiply to find the missing piece. It's like balancing scales to find the unknown value, solving any percent puzzle perfectly.