Finding the Fourth Proportional to 21,488.72, 29,655.60 and 12,057.08

Step by Step Solution

1. Step 1: Write the proportion equation
   21,488.72 : 29,655.60 = 12,057.08 : x
2. Step 2: Convert to fraction form
   21,488.72/29,655.60 = 12,057.08/x
3. Step 3: Cross multiply
   21,488.72x = 29,655.60 × 12,057.08
4. Step 4: Simplify right side
   21,488.72x = 357,559,941.65
5. Step 5: Solve for x
   x = 357,559,941.65/21,488.72
6. Step 6: Final answer
   x = 16,639.42