Finding the Fourth Proportional to 12,612.43, 17,279.12 and 12,139.50

Step by Step Solution

1. Step 1: Write the proportion equation
   12,612.43 : 17,279.12 = 12,139.50 : x
2. Step 2: Convert to fraction form
   12,612.43/17,279.12 = 12,139.50/x
3. Step 3: Cross multiply
   12,612.43x = 17,279.12 × 12,139.50
4. Step 4: Simplify right side
   12,612.43x = 209,759,788.18
5. Step 5: Solve for x
   x = 209,759,788.18/12,612.43
6. Step 6: Final answer
   x = 16,631.19