Finding the Fourth Proportional to 13,156.79, 18,156.14 and 7,188.31

Step by Step Solution

1. Step 1: Write the proportion equation
   13,156.79 : 18,156.14 = 7,188.31 : x
2. Step 2: Convert to fraction form
   13,156.79/18,156.14 = 7,188.31/x
3. Step 3: Cross multiply
   13,156.79x = 18,156.14 × 7,188.31
4. Step 4: Simplify right side
   13,156.79x = 130,511,962.72
5. Step 5: Solve for x
   x = 130,511,962.72/13,156.79
6. Step 6: Final answer
   x = 9,919.74