Finding the Fourth Proportional to 1,321.47, 1,822.77 and 1,005.57

Step by Step Solution

1. Step 1: Write the proportion equation
   1,321.47 : 1,822.77 = 1,005.57 : x
2. Step 2: Convert to fraction form
   1,321.47/1,822.77 = 1,005.57/x
3. Step 3: Cross multiply
   1,321.47x = 1,822.77 × 1,005.57
4. Step 4: Simplify right side
   1,321.47x = 1,832,922.83
5. Step 5: Solve for x
   x = 1,832,922.83/1,321.47
6. Step 6: Final answer
   x = 1,387.03