Finding the Fourth Proportional to 1,019.55, 1,406.53 and 621.06

Step by Step Solution

1. Step 1: Write the proportion equation
   1,019.55 : 1,406.53 = 621.06 : x
2. Step 2: Convert to fraction form
   1,019.55/1,406.53 = 621.06/x
3. Step 3: Cross multiply
   1,019.55x = 1,406.53 × 621.06
4. Step 4: Simplify right side
   1,019.55x = 873,538.08
5. Step 5: Solve for x
   x = 873,538.08/1,019.55
6. Step 6: Final answer
   x = 856.79