Finding the Fourth Proportional to 1,080.78, 1,620.83 and 717.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,080.78 : 1,620.83 = 717.50 : x
2. Step 2: Convert to fraction form
   1,080.78/1,620.83 = 717.50/x
3. Step 3: Cross multiply
   1,080.78x = 1,620.83 × 717.50
4. Step 4: Simplify right side
   1,080.78x = 1,162,945.53
5. Step 5: Solve for x
   x = 1,162,945.53/1,080.78
6. Step 6: Final answer
   x = 1,076.02