Finding the Fourth Proportional to 42,072.96, 63,109.42 and 12,490.78

Step by Step Solution

1. Step 1: Write the proportion equation
   42,072.96 : 63,109.42 = 12,490.78 : x
2. Step 2: Convert to fraction form
   42,072.96/63,109.42 = 12,490.78/x
3. Step 3: Cross multiply
   42,072.96x = 63,109.42 × 12,490.78
4. Step 4: Simplify right side
   42,072.96x = 788,285,881.15
5. Step 5: Solve for x
   x = 788,285,881.15/42,072.96
6. Step 6: Final answer
   x = 18,736.16