Finding the Fourth Proportional to 1,398.47, 1,929.98 and 777.47

Step by Step Solution

1. Step 1: Write the proportion equation
   1,398.47 : 1,929.98 = 777.47 : x
2. Step 2: Convert to fraction form
   1,398.47/1,929.98 = 777.47/x
3. Step 3: Cross multiply
   1,398.47x = 1,929.98 × 777.47
4. Step 4: Simplify right side
   1,398.47x = 1,500,501.55
5. Step 5: Solve for x
   x = 1,500,501.55/1,398.47
6. Step 6: Final answer
   x = 1,072.96