Finding the Fourth Proportional to 1,019.67, 1,406.73 and 621.20

Step by Step Solution

1. Step 1: Write the proportion equation
   1,019.67 : 1,406.73 = 621.20 : x
2. Step 2: Convert to fraction form
   1,019.67/1,406.73 = 621.20/x
3. Step 3: Cross multiply
   1,019.67x = 1,406.73 × 621.20
4. Step 4: Simplify right side
   1,019.67x = 873,853.64
5. Step 5: Solve for x
   x = 873,853.64/1,019.67
6. Step 6: Final answer
   x = 857.00