Finding the Fourth Proportional to 12,957.30, 19,421.55 and 7,118.10

Step by Step Solution

1. Step 1: Write the proportion equation
   12,957.30 : 19,421.55 = 7,118.10 : x
2. Step 2: Convert to fraction form
   12,957.30/19,421.55 = 7,118.10/x
3. Step 3: Cross multiply
   12,957.30x = 19,421.55 × 7,118.10
4. Step 4: Simplify right side
   12,957.30x = 138,244,535.06
5. Step 5: Solve for x
   x = 138,244,535.06/12,957.30
6. Step 6: Final answer
   x = 10,669.24