Finding the Fourth Proportional to 1,405.60, 1,939.72 and 776.12

Step by Step Solution

1. Step 1: Write the proportion equation
   1,405.60 : 1,939.72 = 776.12 : x
2. Step 2: Convert to fraction form
   1,405.60/1,939.72 = 776.12/x
3. Step 3: Cross multiply
   1,405.60x = 1,939.72 × 776.12
4. Step 4: Simplify right side
   1,405.60x = 1,505,455.49
5. Step 5: Solve for x
   x = 1,505,455.49/1,405.60
6. Step 6: Final answer
   x = 1,071.04