Finding the Fourth Proportional to 2,100.83, 3,150.68 and 639.59

Step by Step Solution

1. Step 1: Write the proportion equation
   2,100.83 : 3,150.68 = 639.59 : x
2. Step 2: Convert to fraction form
   2,100.83/3,150.68 = 639.59/x
3. Step 3: Cross multiply
   2,100.83x = 3,150.68 × 639.59
4. Step 4: Simplify right side
   2,100.83x = 2,015,124.47
5. Step 5: Solve for x
   x = 2,015,124.47/2,100.83
6. Step 6: Final answer
   x = 959.21