Finding the Fourth Proportional to 12,979.30, 19,490.55 and 7,140.10

Step by Step Solution

1. Step 1: Write the proportion equation
   12,979.30 : 19,490.55 = 7,140.10 : x
2. Step 2: Convert to fraction form
   12,979.30/19,490.55 = 7,140.10/x
3. Step 3: Cross multiply
   12,979.30x = 19,490.55 × 7,140.10
4. Step 4: Simplify right side
   12,979.30x = 139,164,476.06
5. Step 5: Solve for x
   x = 139,164,476.06/12,979.30
6. Step 6: Final answer
   x = 10,722.03