Finding the Fourth Proportional to 1,398.15, 1,928.43 and 1,065.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,398.15 : 1,928.43 = 1,065.78 : x
2. Step 2: Convert to fraction form
   1,398.15/1,928.43 = 1,065.78/x
3. Step 3: Cross multiply
   1,398.15x = 1,928.43 × 1,065.78
4. Step 4: Simplify right side
   1,398.15x = 2,055,282.13
5. Step 5: Solve for x
   x = 2,055,282.13/1,398.15
6. Step 6: Final answer
   x = 1,470.00