Finding the Fourth Proportional to 2,103.48, 3,155.40 and 642.76

Step by Step Solution

1. Step 1: Write the proportion equation
   2,103.48 : 3,155.40 = 642.76 : x
2. Step 2: Convert to fraction form
   2,103.48/3,155.40 = 642.76/x
3. Step 3: Cross multiply
   2,103.48x = 3,155.40 × 642.76
4. Step 4: Simplify right side
   2,103.48x = 2,028,164.90
5. Step 5: Solve for x
   x = 2,028,164.90/2,103.48
6. Step 6: Final answer
   x = 964.20