Finding the Fourth Proportional to 13,288.59, 18,331.52 and 10,139.31

Step by Step Solution

1. Step 1: Write the proportion equation
   13,288.59 : 18,331.52 = 10,139.31 : x
2. Step 2: Convert to fraction form
   13,288.59/18,331.52 = 10,139.31/x
3. Step 3: Cross multiply
   13,288.59x = 18,331.52 × 10,139.31
4. Step 4: Simplify right side
   13,288.59x = 185,868,913.35
5. Step 5: Solve for x
   x = 185,868,913.35/13,288.59
6. Step 6: Final answer
   x = 13,987.11