Finding the Fourth Proportional to 9,397.87, 12,939.47 and 7,978.75

Step by Step Solution

1. Step 1: Write the proportion equation
   9,397.87 : 12,939.47 = 7,978.75 : x
2. Step 2: Convert to fraction form
   9,397.87/12,939.47 = 7,978.75/x
3. Step 3: Cross multiply
   9,397.87x = 12,939.47 × 7,978.75
4. Step 4: Simplify right side
   9,397.87x = 103,240,731.57
5. Step 5: Solve for x
   x = 103,240,731.57/9,397.87
6. Step 6: Final answer
   x = 10,985.55