Finding the Fourth Proportional to 2,100.32, 3,149.56 and 639.12

Step by Step Solution

1. Step 1: Write the proportion equation
   2,100.32 : 3,149.56 = 639.12 : x
2. Step 2: Convert to fraction form
   2,100.32/3,149.56 = 639.12/x
3. Step 3: Cross multiply
   2,100.32x = 3,149.56 × 639.12
4. Step 4: Simplify right side
   2,100.32x = 2,012,959.40
5. Step 5: Solve for x
   x = 2,012,959.40/2,100.32
6. Step 6: Final answer
   x = 958.41