Finding the Fourth Proportional to 1,099.56, 1,647.83 and 405.56

Step by Step Solution

1. Step 1: Write the proportion equation
   1,099.56 : 1,647.83 = 405.56 : x
2. Step 2: Convert to fraction form
   1,099.56/1,647.83 = 405.56/x
3. Step 3: Cross multiply
   1,099.56x = 1,647.83 × 405.56
4. Step 4: Simplify right side
   1,099.56x = 668,293.93
5. Step 5: Solve for x
   x = 668,293.93/1,099.56
6. Step 6: Final answer
   x = 607.78