Finding the Fourth Proportional to 1,118.81, 1,543.98 and 621.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,118.81 : 1,543.98 = 621.50 : x
2. Step 2: Convert to fraction form
   1,118.81/1,543.98 = 621.50/x
3. Step 3: Cross multiply
   1,118.81x = 1,543.98 × 621.50
4. Step 4: Simplify right side
   1,118.81x = 959,575.85
5. Step 5: Solve for x
   x = 959,575.85/1,118.81
6. Step 6: Final answer
   x = 857.68