Finding the Fourth Proportional to 9,178.12, 12,665.40 and 5,199.15

Step by Step Solution

1. Step 1: Write the proportion equation
   9,178.12 : 12,665.40 = 5,199.15 : x
2. Step 2: Convert to fraction form
   9,178.12/12,665.40 = 5,199.15/x
3. Step 3: Cross multiply
   9,178.12x = 12,665.40 × 5,199.15
4. Step 4: Simplify right side
   9,178.12x = 65,849,314.41
5. Step 5: Solve for x
   x = 65,849,314.41/9,178.12
6. Step 6: Final answer
   x = 7,174.60