Finding the Fourth Proportional to 9,991.29, 13,787.90 and 5,515.04

Step by Step Solution

1. Step 1: Write the proportion equation
   9,991.29 : 13,787.90 = 5,515.04 : x
2. Step 2: Convert to fraction form
   9,991.29/13,787.90 = 5,515.04/x
3. Step 3: Cross multiply
   9,991.29x = 13,787.90 × 5,515.04
4. Step 4: Simplify right side
   9,991.29x = 76,040,868.27
5. Step 5: Solve for x
   x = 76,040,868.27/9,991.29
6. Step 6: Final answer
   x = 7,610.72