Finding the Fourth Proportional to 1,398.76, 1,930.38 and 777.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,398.76 : 1,930.38 = 777.72 : x
2. Step 2: Convert to fraction form
   1,398.76/1,930.38 = 777.72/x
3. Step 3: Cross multiply
   1,398.76x = 1,930.38 × 777.72
4. Step 4: Simplify right side
   1,398.76x = 1,501,295.13
5. Step 5: Solve for x
   x = 1,501,295.13/1,398.76
6. Step 6: Final answer
   x = 1,073.30