Finding the Fourth Proportional to 9,321.74, 12,863.55 and 5,129.90

Step by Step Solution

1. Step 1: Write the proportion equation
   9,321.74 : 12,863.55 = 5,129.90 : x
2. Step 2: Convert to fraction form
   9,321.74/12,863.55 = 5,129.90/x
3. Step 3: Cross multiply
   9,321.74x = 12,863.55 × 5,129.90
4. Step 4: Simplify right side
   9,321.74x = 65,988,725.15
5. Step 5: Solve for x
   x = 65,988,725.15/9,321.74
6. Step 6: Final answer
   x = 7,079.01