We can find the average daily balance of Victor's credit card by using a proportion. Proportions may be used to find missing values in times when we have percentages. The proportion compares two fractions and both sides equal the same amount (that's how we'll know we got the correct answer). The proportion will be written as such: = . To fill in the blanks, we know our "is" is 37. That is the part of the whole that we are looking for, the "of". Our percent is 2.9, and that goes over 100. To solve. we cross multiply 100 x 37, which gives us 3700. Last, we divide by 2.9. After dividing our final answer is 1,275.86. This means that Victor's average daily balance is is $1,275.86.