Finding the Fourth Proportional to 1,078.60, 1,488.46 and 612.76

Step by Step Solution

1. Step 1: Write the proportion equation
   1,078.60 : 1,488.46 = 612.76 : x
2. Step 2: Convert to fraction form
   1,078.60/1,488.46 = 612.76/x
3. Step 3: Cross multiply
   1,078.60x = 1,488.46 × 612.76
4. Step 4: Simplify right side
   1,078.60x = 912,068.75
5. Step 5: Solve for x
   x = 912,068.75/1,078.60
6. Step 6: Final answer
   x = 845.60