Finding the Fourth Proportional to 1,019.97, 1,407.40 and 621.42

Step by Step Solution

1. Step 1: Write the proportion equation
   1,019.97 : 1,407.40 = 621.42 : x
2. Step 2: Convert to fraction form
   1,019.97/1,407.40 = 621.42/x
3. Step 3: Cross multiply
   1,019.97x = 1,407.40 × 621.42
4. Step 4: Simplify right side
   1,019.97x = 874,589.34
5. Step 5: Solve for x
   x = 874,589.34/1,019.97
6. Step 6: Final answer
   x = 857.47