Finding the Fourth Proportional to 1,005.82, 1,388.04 and 612.56

Step by Step Solution

1. Step 1: Write the proportion equation
   1,005.82 : 1,388.04 = 612.56 : x
2. Step 2: Convert to fraction form
   1,005.82/1,388.04 = 612.56/x
3. Step 3: Cross multiply
   1,005.82x = 1,388.04 × 612.56
4. Step 4: Simplify right side
   1,005.82x = 850,258.96
5. Step 5: Solve for x
   x = 850,258.96/1,005.82
6. Step 6: Final answer
   x = 845.34