Finding the Fourth Proportional to 1,135.89, 1,567.83 and 638.69

Step by Step Solution

1. Step 1: Write the proportion equation
   1,135.89 : 1,567.83 = 638.69 : x
2. Step 2: Convert to fraction form
   1,135.89/1,567.83 = 638.69/x
3. Step 3: Cross multiply
   1,135.89x = 1,567.83 × 638.69
4. Step 4: Simplify right side
   1,135.89x = 1,001,354.15
5. Step 5: Solve for x
   x = 1,001,354.15/1,135.89
6. Step 6: Final answer
   x = 881.56