Finding the Fourth Proportional to 1,013.82, 1,399.17 and 621.10

Step by Step Solution

1. Step 1: Write the proportion equation
   1,013.82 : 1,399.17 = 621.10 : x
2. Step 2: Convert to fraction form
   1,013.82/1,399.17 = 621.10/x
3. Step 3: Cross multiply
   1,013.82x = 1,399.17 × 621.10
4. Step 4: Simplify right side
   1,013.82x = 869,024.49
5. Step 5: Solve for x
   x = 869,024.49/1,013.82
6. Step 6: Final answer
   x = 857.18