Finding the Fourth Proportional to 31,137.18, 42,980.39 and 18,390.41

Step by Step Solution

1. Step 1: Write the proportion equation
   31,137.18 : 42,980.39 = 18,390.41 : x
2. Step 2: Convert to fraction form
   31,137.18/42,980.39 = 18,390.41/x
3. Step 3: Cross multiply
   31,137.18x = 42,980.39 × 18,390.41
4. Step 4: Simplify right side
   31,137.18x = 790,426,994.06
5. Step 5: Solve for x
   x = 790,426,994.06/31,137.18
6. Step 6: Final answer
   x = 25,385.31