Finding the Fourth Proportional to 10,978.31, 16,467.47 and 5,139.02

Step by Step Solution

1. Step 1: Write the proportion equation
   10,978.31 : 16,467.47 = 5,139.02 : x
2. Step 2: Convert to fraction form
   10,978.31/16,467.47 = 5,139.02/x
3. Step 3: Cross multiply
   10,978.31x = 16,467.47 × 5,139.02
4. Step 4: Simplify right side
   10,978.31x = 84,626,549.65
5. Step 5: Solve for x
   x = 84,626,549.65/10,978.31
6. Step 6: Final answer
   x = 7,708.53