Finding the Fourth Proportional to 1,638.76, 2,442.41 and 1,625.20

Step by Step Solution

1. Step 1: Write the proportion equation
   1,638.76 : 2,442.41 = 1,625.20 : x
2. Step 2: Convert to fraction form
   1,638.76/2,442.41 = 1,625.20/x
3. Step 3: Cross multiply
   1,638.76x = 2,442.41 × 1,625.20
4. Step 4: Simplify right side
   1,638.76x = 3,969,404.73
5. Step 5: Solve for x
   x = 3,969,404.73/1,638.76
6. Step 6: Final answer
   x = 2,422.20