Finding the Fourth Proportional to 1,041.39, 1,435.62 and 642.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,041.39 : 1,435.62 = 642.78 : x
2. Step 2: Convert to fraction form
   1,041.39/1,435.62 = 642.78/x
3. Step 3: Cross multiply
   1,041.39x = 1,435.62 × 642.78
4. Step 4: Simplify right side
   1,041.39x = 922,784.61
5. Step 5: Solve for x
   x = 922,784.61/1,041.39
6. Step 6: Final answer
   x = 886.11