Finding the Fourth Proportional to 2,100.30, 3,150.42 and 639.54

Step by Step Solution

1. Step 1: Write the proportion equation
   2,100.30 : 3,150.42 = 639.54 : x
2. Step 2: Convert to fraction form
   2,100.30/3,150.42 = 639.54/x
3. Step 3: Cross multiply
   2,100.30x = 3,150.42 × 639.54
4. Step 4: Simplify right side
   2,100.30x = 2,014,819.61
5. Step 5: Solve for x
   x = 2,014,819.61/2,100.30
6. Step 6: Final answer
   x = 959.30