Finding the Fourth Proportional to 1,389.56, 1,917.81 and 829.85

Step by Step Solution

1. Step 1: Write the proportion equation
   1,389.56 : 1,917.81 = 829.85 : x
2. Step 2: Convert to fraction form
   1,389.56/1,917.81 = 829.85/x
3. Step 3: Cross multiply
   1,389.56x = 1,917.81 × 829.85
4. Step 4: Simplify right side
   1,389.56x = 1,591,485.04
5. Step 5: Solve for x
   x = 1,591,485.04/1,389.56
6. Step 6: Final answer
   x = 1,145.32