Finding the Fourth Proportional to 1,152.25, 1,590.15 and 686.77

Step by Step Solution

1. Step 1: Write the proportion equation
   1,152.25 : 1,590.15 = 686.77 : x
2. Step 2: Convert to fraction form
   1,152.25/1,590.15 = 686.77/x
3. Step 3: Cross multiply
   1,152.25x = 1,590.15 × 686.77
4. Step 4: Simplify right side
   1,152.25x = 1,092,067.32
5. Step 5: Solve for x
   x = 1,092,067.32/1,152.25
6. Step 6: Final answer
   x = 947.77