Finding the Fourth Proportional to 9,118.31, 12,581.89 and 5,139.36

Step by Step Solution

1. Step 1: Write the proportion equation
   9,118.31 : 12,581.89 = 5,139.36 : x
2. Step 2: Convert to fraction form
   9,118.31/12,581.89 = 5,139.36/x
3. Step 3: Cross multiply
   9,118.31x = 12,581.89 × 5,139.36
4. Step 4: Simplify right side
   9,118.31x = 64,662,849.34
5. Step 5: Solve for x
   x = 64,662,849.34/9,118.31
6. Step 6: Final answer
   x = 7,091.54