Finding the Fourth Proportional to 1,015.49, 1,400.82 and 621.83

Step by Step Solution

1. Step 1: Write the proportion equation
   1,015.49 : 1,400.82 = 621.83 : x
2. Step 2: Convert to fraction form
   1,015.49/1,400.82 = 621.83/x
3. Step 3: Cross multiply
   1,015.49x = 1,400.82 × 621.83
4. Step 4: Simplify right side
   1,015.49x = 871,071.90
5. Step 5: Solve for x
   x = 871,071.90/1,015.49
6. Step 6: Final answer
   x = 857.78