Finding the Fourth Proportional to 1,398.71, 1,930.31 and 777.71

Step by Step Solution

1. Step 1: Write the proportion equation
   1,398.71 : 1,930.31 = 777.71 : x
2. Step 2: Convert to fraction form
   1,398.71/1,930.31 = 777.71/x
3. Step 3: Cross multiply
   1,398.71x = 1,930.31 × 777.71
4. Step 4: Simplify right side
   1,398.71x = 1,501,217.50
5. Step 5: Solve for x
   x = 1,501,217.50/1,398.71
6. Step 6: Final answer
   x = 1,073.29