Finding the Fourth Proportional to 1,191.28, 1,785.89 and 642.83

Step by Step Solution

1. Step 1: Write the proportion equation
   1,191.28 : 1,785.89 = 642.83 : x
2. Step 2: Convert to fraction form
   1,191.28/1,785.89 = 642.83/x
3. Step 3: Cross multiply
   1,191.28x = 1,785.89 × 642.83
4. Step 4: Simplify right side
   1,191.28x = 1,148,023.67
5. Step 5: Solve for x
   x = 1,148,023.67/1,191.28
6. Step 6: Final answer
   x = 963.69