Finding the Fourth Proportional to 11,329.79, 15,605.78 and 7,920.77

Step by Step Solution

1. Step 1: Write the proportion equation
   11,329.79 : 15,605.78 = 7,920.77 : x
2. Step 2: Convert to fraction form
   11,329.79/15,605.78 = 7,920.77/x
3. Step 3: Cross multiply
   11,329.79x = 15,605.78 × 7,920.77
4. Step 4: Simplify right side
   11,329.79x = 123,609,676.42
5. Step 5: Solve for x
   x = 123,609,676.42/11,329.79
6. Step 6: Final answer
   x = 10,910.15