Finding the Fourth Proportional to 12,978.27, 19,489.28 and 12,876.21

Step by Step Solution

1. Step 1: Write the proportion equation
   12,978.27 : 19,489.28 = 12,876.21 : x
2. Step 2: Convert to fraction form
   12,978.27/19,489.28 = 12,876.21/x
3. Step 3: Cross multiply
   12,978.27x = 19,489.28 × 12,876.21
4. Step 4: Simplify right side
   12,978.27x = 250,947,997.65
5. Step 5: Solve for x
   x = 250,947,997.65/12,978.27
6. Step 6: Final answer
   x = 19,336.01