Finding the Fourth Proportional to 31,059.62, 42,851.34 and 20,310.78

Step by Step Solution

1. Step 1: Write the proportion equation
   31,059.62 : 42,851.34 = 20,310.78 : x
2. Step 2: Convert to fraction form
   31,059.62/42,851.34 = 20,310.78/x
3. Step 3: Cross multiply
   31,059.62x = 42,851.34 × 20,310.78
4. Step 4: Simplify right side
   31,059.62x = 870,344,037.89
5. Step 5: Solve for x
   x = 870,344,037.89/31,059.62
6. Step 6: Final answer
   x = 28,021.73