Finding the Fourth Proportional to 21,388.59, 29,511.54 and 12,431.48

Step by Step Solution

1. Step 1: Write the proportion equation
   21,388.59 : 29,511.54 = 12,431.48 : x
2. Step 2: Convert to fraction form
   21,388.59/29,511.54 = 12,431.48/x
3. Step 3: Cross multiply
   21,388.59x = 29,511.54 × 12,431.48
4. Step 4: Simplify right side
   21,388.59x = 366,871,971.72
5. Step 5: Solve for x
   x = 366,871,971.72/21,388.59
6. Step 6: Final answer
   x = 17,152.70