Write the Word or Phrase That Best Completes Each Statement $$I = P R T \text {, where } I \text { is the simple interest on a principal of } P \text { dollars at a rate of interest } R \text { per year }$$

Write the word or phrase that best completes each statement or answers the question.
Write a sentence that expresses the relationship in the formula, using the language of variation or proportion.
- $$I = P R T \text {, where } I \text { is the simple interest on a principal of } P \text { dollars at a rate of interest } R \text { per year }$$