Finding the Fourth Proportional to 1,429.20, 1,972.32 and 839.75

Step by Step Solution

1. Step 1: Write the proportion equation
   1,429.20 : 1,972.32 = 839.75 : x
2. Step 2: Convert to fraction form
   1,429.20/1,972.32 = 839.75/x
3. Step 3: Cross multiply
   1,429.20x = 1,972.32 × 839.75
4. Step 4: Simplify right side
   1,429.20x = 1,656,250.11
5. Step 5: Solve for x
   x = 1,656,250.11/1,429.20
6. Step 6: Final answer
   x = 1,158.86