Finding the Fourth Proportional to 21,085.71, 31,604.54 and 7,042.47

Step by Step Solution

1. Step 1: Write the proportion equation
   21,085.71 : 31,604.54 = 7,042.47 : x
2. Step 2: Convert to fraction form
   21,085.71/31,604.54 = 7,042.47/x
3. Step 3: Cross multiply
   21,085.71x = 31,604.54 × 7,042.47
4. Step 4: Simplify right side
   21,085.71x = 222,573,989.60
5. Step 5: Solve for x
   x = 222,573,989.60/21,085.71
6. Step 6: Final answer
   x = 10,555.68