Finding the Fourth Proportional to 22,128.12, 30,534.30 and 12,699.72

Step by Step Solution

1. Step 1: Write the proportion equation
   22,128.12 : 30,534.30 = 12,699.72 : x
2. Step 2: Convert to fraction form
   22,128.12/30,534.30 = 12,699.72/x
3. Step 3: Cross multiply
   22,128.12x = 30,534.30 × 12,699.72
4. Step 4: Simplify right side
   22,128.12x = 387,777,060.40
5. Step 5: Solve for x
   x = 387,777,060.40/22,128.12
6. Step 6: Final answer
   x = 17,524.18