Finding the Fourth Proportional to 31,005.76, 42,771.36 and 21,557.92

Step by Step Solution

1. Step 1: Write the proportion equation
   31,005.76 : 42,771.36 = 21,557.92 : x
2. Step 2: Convert to fraction form
   31,005.76/42,771.36 = 21,557.92/x
3. Step 3: Cross multiply
   31,005.76x = 42,771.36 × 21,557.92
4. Step 4: Simplify right side
   31,005.76x = 922,061,557.17
5. Step 5: Solve for x
   x = 922,061,557.17/31,005.76
6. Step 6: Final answer
   x = 29,738.40