Finding the Fourth Proportional to 2,100.67, 3,150.09 and 639.48

Step by Step Solution

1. Step 1: Write the proportion equation
   2,100.67 : 3,150.09 = 639.48 : x
2. Step 2: Convert to fraction form
   2,100.67/3,150.09 = 639.48/x
3. Step 3: Cross multiply
   2,100.67x = 3,150.09 × 639.48
4. Step 4: Simplify right side
   2,100.67x = 2,014,419.55
5. Step 5: Solve for x
   x = 2,014,419.55/2,100.67
6. Step 6: Final answer
   x = 958.94