Finding the Fourth Proportional to 1,384.75, 1,910.96 and 860.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,384.75 : 1,910.96 = 860.78 : x
2. Step 2: Convert to fraction form
   1,384.75/1,910.96 = 860.78/x
3. Step 3: Cross multiply
   1,384.75x = 1,910.96 × 860.78
4. Step 4: Simplify right side
   1,384.75x = 1,644,916.15
5. Step 5: Solve for x
   x = 1,644,916.15/1,384.75
6. Step 6: Final answer
   x = 1,187.88