Finding the Fourth Proportional to 31,089.78, 42,909.42 and 18,342.18

Step by Step Solution

1. Step 1: Write the proportion equation
   31,089.78 : 42,909.42 = 18,342.18 : x
2. Step 2: Convert to fraction form
   31,089.78/42,909.42 = 18,342.18/x
3. Step 3: Cross multiply
   31,089.78x = 42,909.42 × 18,342.18
4. Step 4: Simplify right side
   31,089.78x = 787,052,305.34
5. Step 5: Solve for x
   x = 787,052,305.34/31,089.78
6. Step 6: Final answer
   x = 25,315.47