Finding the Fourth Proportional to 1,398.50, 1,929.94 and 777.62

Step by Step Solution

1. Step 1: Write the proportion equation
   1,398.50 : 1,929.94 = 777.62 : x
2. Step 2: Convert to fraction form
   1,398.50/1,929.94 = 777.62/x
3. Step 3: Cross multiply
   1,398.50x = 1,929.94 × 777.62
4. Step 4: Simplify right side
   1,398.50x = 1,500,759.94
5. Step 5: Solve for x
   x = 1,500,759.94/1,398.50
6. Step 6: Final answer
   x = 1,073.12