Finding the Fourth Proportional to 1,405.13, 1,939.05 and 775.68

Step by Step Solution

1. Step 1: Write the proportion equation
   1,405.13 : 1,939.05 = 775.68 : x
2. Step 2: Convert to fraction form
   1,405.13/1,939.05 = 775.68/x
3. Step 3: Cross multiply
   1,405.13x = 1,939.05 × 775.68
4. Step 4: Simplify right side
   1,405.13x = 1,504,082.30
5. Step 5: Solve for x
   x = 1,504,082.30/1,405.13
6. Step 6: Final answer
   x = 1,070.42