Finding the Fourth Proportional to 1,014.42, 1,399.86 and 621.57

Step by Step Solution

1. Step 1: Write the proportion equation
   1,014.42 : 1,399.86 = 621.57 : x
2. Step 2: Convert to fraction form
   1,014.42/1,399.86 = 621.57/x
3. Step 3: Cross multiply
   1,014.42x = 1,399.86 × 621.57
4. Step 4: Simplify right side
   1,014.42x = 870,110.98
5. Step 5: Solve for x
   x = 870,110.98/1,014.42
6. Step 6: Final answer
   x = 857.74