Finding the Fourth Proportional to 2,103.56, 3,155.34 and 642.71

Step by Step Solution

1. Step 1: Write the proportion equation
   2,103.56 : 3,155.34 = 642.71 : x
2. Step 2: Convert to fraction form
   2,103.56/3,155.34 = 642.71/x
3. Step 3: Cross multiply
   2,103.56x = 3,155.34 × 642.71
4. Step 4: Simplify right side
   2,103.56x = 2,027,954.40
5. Step 5: Solve for x
   x = 2,027,954.40/2,103.56
6. Step 6: Final answer
   x = 964.06