Answer:
43%
Explanation:
If there are 43 yellow marbles out of 100 total, the fraction that will be used is 43/100. The percentage is found by dividing the numerator (top) by the denominator (bottom). The percentage is the first two numbers in the decimal. For future reference, if a decimal were to have more than 2 or 3 digits, the number would be rounded to the 4th and the decimal point would be placed between the 2nd and 3rd digits.