Finding the Fourth Proportional to 1,128.15, 1,556.82 and 630.81

Step by Step Solution

1. Step 1: Write the proportion equation
   1,128.15 : 1,556.82 = 630.81 : x
2. Step 2: Convert to fraction form
   1,128.15/1,556.82 = 630.81/x
3. Step 3: Cross multiply
   1,128.15x = 1,556.82 × 630.81
4. Step 4: Simplify right side
   1,128.15x = 982,057.62
5. Step 5: Solve for x
   x = 982,057.62/1,128.15
6. Step 6: Final answer
   x = 870.50