Finding the Fourth Proportional to 1,380.87, 1,905.98 and 814.20

Step by Step Solution

1. Step 1: Write the proportion equation
   1,380.87 : 1,905.98 = 814.20 : x
2. Step 2: Convert to fraction form
   1,380.87/1,905.98 = 814.20/x
3. Step 3: Cross multiply
   1,380.87x = 1,905.98 × 814.20
4. Step 4: Simplify right side
   1,380.87x = 1,551,844.85
5. Step 5: Solve for x
   x = 1,551,844.85/1,380.87
6. Step 6: Final answer
   x = 1,123.82