Finding the Fourth Proportional to 1,317.50, 1,818.31 and 765.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,317.50 : 1,818.31 = 765.50 : x
2. Step 2: Convert to fraction form
   1,317.50/1,818.31 = 765.50/x
3. Step 3: Cross multiply
   1,317.50x = 1,818.31 × 765.50
4. Step 4: Simplify right side
   1,317.50x = 1,391,916.31
5. Step 5: Solve for x
   x = 1,391,916.31/1,317.50
6. Step 6: Final answer
   x = 1,056.48