Finding the Fourth Proportional to 21,835.76, 30,129.72 and 12,400.88

Step by Step Solution

1. Step 1: Write the proportion equation
   21,835.76 : 30,129.72 = 12,400.88 : x
2. Step 2: Convert to fraction form
   21,835.76/30,129.72 = 12,400.88/x
3. Step 3: Cross multiply
   21,835.76x = 30,129.72 × 12,400.88
4. Step 4: Simplify right side
   21,835.76x = 373,635,042.15
5. Step 5: Solve for x
   x = 373,635,042.15/21,835.76
6. Step 6: Final answer
   x = 17,111.15