Finding the Fourth Proportional to 1,398.25, 1,929.59 and 777.25

Step by Step Solution

1. Step 1: Write the proportion equation
   1,398.25 : 1,929.59 = 777.25 : x
2. Step 2: Convert to fraction form
   1,398.25/1,929.59 = 777.25/x
3. Step 3: Cross multiply
   1,398.25x = 1,929.59 × 777.25
4. Step 4: Simplify right side
   1,398.25x = 1,499,773.83
5. Step 5: Solve for x
   x = 1,499,773.83/1,398.25
6. Step 6: Final answer
   x = 1,072.61