Finding the Fourth Proportional to 19,978.15, 27,579.83 and 12,426.91

Step by Step Solution

1. Step 1: Write the proportion equation
   19,978.15 : 27,579.83 = 12,426.91 : x
2. Step 2: Convert to fraction form
   19,978.15/27,579.83 = 12,426.91/x
3. Step 3: Cross multiply
   19,978.15x = 27,579.83 × 12,426.91
4. Step 4: Simplify right side
   19,978.15x = 342,731,934.14
5. Step 5: Solve for x
   x = 342,731,934.14/19,978.15
6. Step 6: Final answer
   x = 17,155.34