Finding the Fourth Proportional to 1,620.78, 2,429.49 and 851.82

Step by Step Solution

1. Step 1: Write the proportion equation
   1,620.78 : 2,429.49 = 851.82 : x
2. Step 2: Convert to fraction form
   1,620.78/2,429.49 = 851.82/x
3. Step 3: Cross multiply
   1,620.78x = 2,429.49 × 851.82
4. Step 4: Simplify right side
   1,620.78x = 2,069,488.17
5. Step 5: Solve for x
   x = 2,069,488.17/1,620.78
6. Step 6: Final answer
   x = 1,276.85