Finding the Fourth Proportional to 1,118.72, 1,543.82 and 621.34

Step by Step Solution

1. Step 1: Write the proportion equation
   1,118.72 : 1,543.82 = 621.34 : x
2. Step 2: Convert to fraction form
   1,118.72/1,543.82 = 621.34/x
3. Step 3: Cross multiply
   1,118.72x = 1,543.82 × 621.34
4. Step 4: Simplify right side
   1,118.72x = 959,237.12
5. Step 5: Solve for x
   x = 959,237.12/1,118.72
6. Step 6: Final answer
   x = 857.44