Finding the Fourth Proportional to 9,991.89, 13,788.33 and 5,739.96

Step by Step Solution

1. Step 1: Write the proportion equation
   9,991.89 : 13,788.33 = 5,739.96 : x
2. Step 2: Convert to fraction form
   9,991.89/13,788.33 = 5,739.96/x
3. Step 3: Cross multiply
   9,991.89x = 13,788.33 × 5,739.96
4. Step 4: Simplify right side
   9,991.89x = 79,144,462.67
5. Step 5: Solve for x
   x = 79,144,462.67/9,991.89
6. Step 6: Final answer
   x = 7,920.87