Finding the Fourth Proportional to 1,380.15, 1,902.42 and 1,020.61

Step by Step Solution

1. Step 1: Write the proportion equation
   1,380.15 : 1,902.42 = 1,020.61 : x
2. Step 2: Convert to fraction form
   1,380.15/1,902.42 = 1,020.61/x
3. Step 3: Cross multiply
   1,380.15x = 1,902.42 × 1,020.61
4. Step 4: Simplify right side
   1,380.15x = 1,941,631.25
5. Step 5: Solve for x
   x = 1,941,631.25/1,380.15
6. Step 6: Final answer
   x = 1,406.83