Finding the Fourth Proportional to 1,128.57, 1,556.96 and 708.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,128.57 : 1,556.96 = 708.78 : x
2. Step 2: Convert to fraction form
   1,128.57/1,556.96 = 708.78/x
3. Step 3: Cross multiply
   1,128.57x = 1,556.96 × 708.78
4. Step 4: Simplify right side
   1,128.57x = 1,103,544.40
5. Step 5: Solve for x
   x = 1,103,544.40/1,128.57
6. Step 6: Final answer
   x = 977.83