Finding the Fourth Proportional to 42,128, 58,153.60 and 28,712.81

Step by Step Solution

1. Step 1: Write the proportion equation
   42,128 : 58,153.60 = 28,712.81 : x
2. Step 2: Convert to fraction form
   42,128/58,153.60 = 28,712.81/x
3. Step 3: Cross multiply
   42,128x = 58,153.60 × 28,712.81
4. Step 4: Simplify right side
   42,128x = 1,669,753,267.62
5. Step 5: Solve for x
   x = 1,669,753,267.62/42,128
6. Step 6: Final answer
   x = 39,635.24