Finding the Fourth Proportional to 19,978.16, 27,579.83 and 12,426.90

Step by Step Solution

1. Step 1: Write the proportion equation
   19,978.16 : 27,579.83 = 12,426.90 : x
2. Step 2: Convert to fraction form
   19,978.16/27,579.83 = 12,426.90/x
3. Step 3: Cross multiply
   19,978.16x = 27,579.83 × 12,426.90
4. Step 4: Simplify right side
   19,978.16x = 342,731,727.29
5. Step 5: Solve for x
   x = 342,731,727.29/19,978.16
6. Step 6: Final answer
   x = 17,155.32