Finding the Fourth Proportional to 21,688.89, 29,932.61 and 13,628.13

Step by Step Solution

1. Step 1: Write the proportion equation
   21,688.89 : 29,932.61 = 13,628.13 : x
2. Step 2: Convert to fraction form
   21,688.89/29,932.61 = 13,628.13/x
3. Step 3: Cross multiply
   21,688.89x = 29,932.61 × 13,628.13
4. Step 4: Simplify right side
   21,688.89x = 407,925,500.32
5. Step 5: Solve for x
   x = 407,925,500.32/21,688.89
6. Step 6: Final answer
   x = 18,808.04