Finding the Fourth Proportional to 9,405.03, 12,978.81 and 5,156.43

Step by Step Solution

1. Step 1: Write the proportion equation
   9,405.03 : 12,978.81 = 5,156.43 : x
2. Step 2: Convert to fraction form
   9,405.03/12,978.81 = 5,156.43/x
3. Step 3: Cross multiply
   9,405.03x = 12,978.81 × 5,156.43
4. Step 4: Simplify right side
   9,405.03x = 66,924,325.25
5. Step 5: Solve for x
   x = 66,924,325.25/9,405.03
6. Step 6: Final answer
   x = 7,115.80