Finding the Fourth Proportional to 9,139.32, 12,612.30 and 5,160.48

Step by Step Solution

1. Step 1: Write the proportion equation
   9,139.32 : 12,612.30 = 5,160.48 : x
2. Step 2: Convert to fraction form
   9,139.32/12,612.30 = 5,160.48/x
3. Step 3: Cross multiply
   9,139.32x = 12,612.30 × 5,160.48
4. Step 4: Simplify right side
   9,139.32x = 65,085,521.90
5. Step 5: Solve for x
   x = 65,085,521.90/9,139.32
6. Step 6: Final answer
   x = 7,121.48