Finding the Fourth Proportional to 31,140.87, 42,961.29 and 21,714.90

Step by Step Solution

1. Step 1: Write the proportion equation
   31,140.87 : 42,961.29 = 21,714.90 : x
2. Step 2: Convert to fraction form
   31,140.87/42,961.29 = 21,714.90/x
3. Step 3: Cross multiply
   31,140.87x = 42,961.29 × 21,714.90
4. Step 4: Simplify right side
   31,140.87x = 932,900,116.22
5. Step 5: Solve for x
   x = 932,900,116.22/31,140.87
6. Step 6: Final answer
   x = 29,957.42