Finding the Fourth Proportional to 1,152.16, 1,590.32 and 686.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,152.16 : 1,590.32 = 686.72 : x
2. Step 2: Convert to fraction form
   1,152.16/1,590.32 = 686.72/x
3. Step 3: Cross multiply
   1,152.16x = 1,590.32 × 686.72
4. Step 4: Simplify right side
   1,152.16x = 1,092,104.55
5. Step 5: Solve for x
   x = 1,092,104.55/1,152.16
6. Step 6: Final answer
   x = 947.88