Finding the Fourth Proportional to 1,128.17, 1,556.79 and 630.69

Step by Step Solution

1. Step 1: Write the proportion equation
   1,128.17 : 1,556.79 = 630.69 : x
2. Step 2: Convert to fraction form
   1,128.17/1,556.79 = 630.69/x
3. Step 3: Cross multiply
   1,128.17x = 1,556.79 × 630.69
4. Step 4: Simplify right side
   1,128.17x = 981,851.89
5. Step 5: Solve for x
   x = 981,851.89/1,128.17
6. Step 6: Final answer
   x = 870.31