Finding the Fourth Proportional to 1,118.69, 1,543.81 and 621.39

Step by Step Solution

1. Step 1: Write the proportion equation
   1,118.69 : 1,543.81 = 621.39 : x
2. Step 2: Convert to fraction form
   1,118.69/1,543.81 = 621.39/x
3. Step 3: Cross multiply
   1,118.69x = 1,543.81 × 621.39
4. Step 4: Simplify right side
   1,118.69x = 959,304.81
5. Step 5: Solve for x
   x = 959,304.81/1,118.69
6. Step 6: Final answer
   x = 857.52