Finding the Fourth Proportional to 1,387.50, 1,914.76 and 766.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,387.50 : 1,914.76 = 766.50 : x
2. Step 2: Convert to fraction form
   1,387.50/1,914.76 = 766.50/x
3. Step 3: Cross multiply
   1,387.50x = 1,914.76 × 766.50
4. Step 4: Simplify right side
   1,387.50x = 1,467,663.54
5. Step 5: Solve for x
   x = 1,467,663.54/1,387.50
6. Step 6: Final answer
   x = 1,057.78