Finding the Fourth Proportional to 1,385.56, 1,921.18 and 1,339.30

Step by Step Solution

1. Step 1: Write the proportion equation
   1,385.56 : 1,921.18 = 1,339.30 : x
2. Step 2: Convert to fraction form
   1,385.56/1,921.18 = 1,339.30/x
3. Step 3: Cross multiply
   1,385.56x = 1,921.18 × 1,339.30
4. Step 4: Simplify right side
   1,385.56x = 2,573,036.37
5. Step 5: Solve for x
   x = 2,573,036.37/1,385.56
6. Step 6: Final answer
   x = 1,857.04