Finding the Fourth Proportional to 13,383.47, 18,471.78 and 7,721.88

Step by Step Solution

1. Step 1: Write the proportion equation
   13,383.47 : 18,471.78 = 7,721.88 : x
2. Step 2: Convert to fraction form
   13,383.47/18,471.78 = 7,721.88/x
3. Step 3: Cross multiply
   13,383.47x = 18,471.78 × 7,721.88
4. Step 4: Simplify right side
   13,383.47x = 142,636,799.28
5. Step 5: Solve for x
   x = 142,636,799.28/13,383.47
6. Step 6: Final answer
   x = 10,657.68