Finding the Fourth Proportional to 31,156.14, 42,990.40 and 18,407.55

Step by Step Solution

1. Step 1: Write the proportion equation
   31,156.14 : 42,990.40 = 18,407.55 : x
2. Step 2: Convert to fraction form
   31,156.14/42,990.40 = 18,407.55/x
3. Step 3: Cross multiply
   31,156.14x = 42,990.40 × 18,407.55
4. Step 4: Simplify right side
   31,156.14x = 791,347,937.52
5. Step 5: Solve for x
   x = 791,347,937.52/31,156.14
6. Step 6: Final answer
   x = 25,399.42