Finding the Fourth Proportional to 1,405.69, 1,939.81 and 776.19

Step by Step Solution

1. Step 1: Write the proportion equation
   1,405.69 : 1,939.81 = 776.19 : x
2. Step 2: Convert to fraction form
   1,405.69/1,939.81 = 776.19/x
3. Step 3: Cross multiply
   1,405.69x = 1,939.81 × 776.19
4. Step 4: Simplify right side
   1,405.69x = 1,505,661.12
5. Step 5: Solve for x
   x = 1,505,661.12/1,405.69
6. Step 6: Final answer
   x = 1,071.12