Finding the Fourth Proportional to 1,006.56, 1,389.15 and 613.85

Step by Step Solution

1. Step 1: Write the proportion equation
   1,006.56 : 1,389.15 = 613.85 : x
2. Step 2: Convert to fraction form
   1,006.56/1,389.15 = 613.85/x
3. Step 3: Cross multiply
   1,006.56x = 1,389.15 × 613.85
4. Step 4: Simplify right side
   1,006.56x = 852,722.78
5. Step 5: Solve for x
   x = 852,722.78/1,006.56
6. Step 6: Final answer
   x = 847.17