Finding the Fourth Proportional to 1,078.71, 1,488.54 and 612.96

Step by Step Solution

1. Step 1: Write the proportion equation
   1,078.71 : 1,488.54 = 612.96 : x
2. Step 2: Convert to fraction form
   1,078.71/1,488.54 = 612.96/x
3. Step 3: Cross multiply
   1,078.71x = 1,488.54 × 612.96
4. Step 4: Simplify right side
   1,078.71x = 912,415.48
5. Step 5: Solve for x
   x = 912,415.48/1,078.71
6. Step 6: Final answer
   x = 845.84