Finding the Fourth Proportional to 1,311.50, 1,966.86 and 617.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,311.50 : 1,966.86 = 617.78 : x
2. Step 2: Convert to fraction form
   1,311.50/1,966.86 = 617.78/x
3. Step 3: Cross multiply
   1,311.50x = 1,966.86 × 617.78
4. Step 4: Simplify right side
   1,311.50x = 1,215,086.77
5. Step 5: Solve for x
   x = 1,215,086.77/1,311.50
6. Step 6: Final answer
   x = 926.49