Finding the Fourth Proportional to 1,191.47, 1,644.24 and 667.61

Step by Step Solution

1. Step 1: Write the proportion equation
   1,191.47 : 1,644.24 = 667.61 : x
2. Step 2: Convert to fraction form
   1,191.47/1,644.24 = 667.61/x
3. Step 3: Cross multiply
   1,191.47x = 1,644.24 × 667.61
4. Step 4: Simplify right side
   1,191.47x = 1,097,702.85
5. Step 5: Solve for x
   x = 1,097,702.85/1,191.47
6. Step 6: Final answer
   x = 921.31