Finding the Fourth Proportional to 2,102.72, 3,155.52 and 1,129.12

Step by Step Solution

1. Step 1: Write the proportion equation
   2,102.72 : 3,155.52 = 1,129.12 : x
2. Step 2: Convert to fraction form
   2,102.72/3,155.52 = 1,129.12/x
3. Step 3: Cross multiply
   2,102.72x = 3,155.52 × 1,129.12
4. Step 4: Simplify right side
   2,102.72x = 3,562,960.74
5. Step 5: Solve for x
   x = 3,562,960.74/2,102.72
6. Step 6: Final answer
   x = 1,694.45