Finding the Fourth Proportional to 21,470.78, 29,629.98 and 12,971.72

Step by Step Solution

1. Step 1: Write the proportion equation
   21,470.78 : 29,629.98 = 12,971.72 : x
2. Step 2: Convert to fraction form
   21,470.78/29,629.98 = 12,971.72/x
3. Step 3: Cross multiply
   21,470.78x = 29,629.98 × 12,971.72
4. Step 4: Simplify right side
   21,470.78x = 384,351,804.17
5. Step 5: Solve for x
   x = 384,351,804.17/21,470.78
6. Step 6: Final answer
   x = 17,901.16