Finding the Fourth Proportional to 1,118.69, 1,543.86 and 621.38

Step by Step Solution

1. Step 1: Write the proportion equation
   1,118.69 : 1,543.86 = 621.38 : x
2. Step 2: Convert to fraction form
   1,118.69/1,543.86 = 621.38/x
3. Step 3: Cross multiply
   1,118.69x = 1,543.86 × 621.38
4. Step 4: Simplify right side
   1,118.69x = 959,320.62
5. Step 5: Solve for x
   x = 959,320.62/1,118.69
6. Step 6: Final answer
   x = 857.54