Finding the Fourth Proportional to 1,128.13, 1,556.83 and 630.77

Step by Step Solution

1. Step 1: Write the proportion equation
   1,128.13 : 1,556.83 = 630.77 : x
2. Step 2: Convert to fraction form
   1,128.13/1,556.83 = 630.77/x
3. Step 3: Cross multiply
   1,128.13x = 1,556.83 × 630.77
4. Step 4: Simplify right side
   1,128.13x = 982,010.88
5. Step 5: Solve for x
   x = 982,010.88/1,128.13
6. Step 6: Final answer
   x = 870.48