Finding the Fourth Proportional to 1,152.57, 1,590.56 and 628.61

Step by Step Solution

1. Step 1: Write the proportion equation
   1,152.57 : 1,590.56 = 628.61 : x
2. Step 2: Convert to fraction form
   1,152.57/1,590.56 = 628.61/x
3. Step 3: Cross multiply
   1,152.57x = 1,590.56 × 628.61
4. Step 4: Simplify right side
   1,152.57x = 999,830.83
5. Step 5: Solve for x
   x = 999,830.83/1,152.57
6. Step 6: Final answer
   x = 867.48