Finding the Fourth Proportional to 1,385.55, 2,076.17 and 871.47

Step by Step Solution

1. Step 1: Write the proportion equation
   1,385.55 : 2,076.17 = 871.47 : x
2. Step 2: Convert to fraction form
   1,385.55/2,076.17 = 871.47/x
3. Step 3: Cross multiply
   1,385.55x = 2,076.17 × 871.47
4. Step 4: Simplify right side
   1,385.55x = 1,809,315.51
5. Step 5: Solve for x
   x = 1,809,315.51/1,385.55
6. Step 6: Final answer
   x = 1,305.85