Finding the Fourth Proportional to 30,630.78, 42,280.74 and 20,555.82

Step by Step Solution

1. Step 1: Write the proportion equation
   30,630.78 : 42,280.74 = 20,555.82 : x
2. Step 2: Convert to fraction form
   30,630.78/42,280.74 = 20,555.82/x
3. Step 3: Cross multiply
   30,630.78x = 42,280.74 × 20,555.82
4. Step 4: Simplify right side
   30,630.78x = 869,115,280.91
5. Step 5: Solve for x
   x = 869,115,280.91/30,630.78
6. Step 6: Final answer
   x = 28,373.92