Finding the Fourth Proportional to 9,157.50, 12,639.24 and 5,178.78

Step by Step Solution

1. Step 1: Write the proportion equation
   9,157.50 : 12,639.24 = 5,178.78 : x
2. Step 2: Convert to fraction form
   9,157.50/12,639.24 = 5,178.78/x
3. Step 3: Cross multiply
   9,157.50x = 12,639.24 × 5,178.78
4. Step 4: Simplify right side
   9,157.50x = 65,455,843.33
5. Step 5: Solve for x
   x = 65,455,843.33/9,157.50
6. Step 6: Final answer
   x = 7,147.79