Finding the Fourth Proportional to 1,406.28, 1,940.58 and 776.80

Step by Step Solution

1. Step 1: Write the proportion equation
   1,406.28 : 1,940.58 = 776.80 : x
2. Step 2: Convert to fraction form
   1,406.28/1,940.58 = 776.80/x
3. Step 3: Cross multiply
   1,406.28x = 1,940.58 × 776.80
4. Step 4: Simplify right side
   1,406.28x = 1,507,442.54
5. Step 5: Solve for x
   x = 1,507,442.54/1,406.28
6. Step 6: Final answer
   x = 1,071.94