Finding the Fourth Proportional to 1,288.72, 1,777.12 and 1,102.83

Step by Step Solution

1. Step 1: Write the proportion equation
   1,288.72 : 1,777.12 = 1,102.83 : x
2. Step 2: Convert to fraction form
   1,288.72/1,777.12 = 1,102.83/x
3. Step 3: Cross multiply
   1,288.72x = 1,777.12 × 1,102.83
4. Step 4: Simplify right side
   1,288.72x = 1,959,861.25
5. Step 5: Solve for x
   x = 1,959,861.25/1,288.72
6. Step 6: Final answer
   x = 1,520.78