Finding the Fourth Proportional to 2,100.38, 3,150.48 and 639.49

Step by Step Solution

1. Step 1: Write the proportion equation
   2,100.38 : 3,150.48 = 639.49 : x
2. Step 2: Convert to fraction form
   2,100.38/3,150.48 = 639.49/x
3. Step 3: Cross multiply
   2,100.38x = 3,150.48 × 639.49
4. Step 4: Simplify right side
   2,100.38x = 2,014,700.46
5. Step 5: Solve for x
   x = 2,014,700.46/2,100.38
6. Step 6: Final answer
   x = 959.21