Finding the Fourth Proportional to 10,979.31, 16,478.28 and 5,438.91

Step by Step Solution

1. Step 1: Write the proportion equation
   10,979.31 : 16,478.28 = 5,438.91 : x
2. Step 2: Convert to fraction form
   10,979.31/16,478.28 = 5,438.91/x
3. Step 3: Cross multiply
   10,979.31x = 16,478.28 × 5,438.91
4. Step 4: Simplify right side
   10,979.31x = 89,623,881.87
5. Step 5: Solve for x
   x = 89,623,881.87/10,979.31
6. Step 6: Final answer
   x = 8,162.98