Finding the Fourth Proportional to 1,392.10, 2,086.32 and 776.09

Step by Step Solution

1. Step 1: Write the proportion equation
   1,392.10 : 2,086.32 = 776.09 : x
2. Step 2: Convert to fraction form
   1,392.10/2,086.32 = 776.09/x
3. Step 3: Cross multiply
   1,392.10x = 2,086.32 × 776.09
4. Step 4: Simplify right side
   1,392.10x = 1,619,177.30
5. Step 5: Solve for x
   x = 1,619,177.30/1,392.10
6. Step 6: Final answer
   x = 1,163.12