Finding the Fourth Proportional to 1,128.60, 1,557.90 and 976.56

Step by Step Solution

1. Step 1: Write the proportion equation
   1,128.60 : 1,557.90 = 976.56 : x
2. Step 2: Convert to fraction form
   1,128.60/1,557.90 = 976.56/x
3. Step 3: Cross multiply
   1,128.60x = 1,557.90 × 976.56
4. Step 4: Simplify right side
   1,128.60x = 1,521,382.82
5. Step 5: Solve for x
   x = 1,521,382.82/1,128.60
6. Step 6: Final answer
   x = 1,348.03