Finding the Fourth Proportional to 21,308.40, 29,405.52 and 12,357.72

Step by Step Solution

1. Step 1: Write the proportion equation
   21,308.40 : 29,405.52 = 12,357.72 : x
2. Step 2: Convert to fraction form
   21,308.40/29,405.52 = 12,357.72/x
3. Step 3: Cross multiply
   21,308.40x = 29,405.52 × 12,357.72
4. Step 4: Simplify right side
   21,308.40x = 363,385,182.61
5. Step 5: Solve for x
   x = 363,385,182.61/21,308.40
6. Step 6: Final answer
   x = 17,053.61